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From Flowcharts to Python
2
This Activity Workbook introduces students who already know flowchart fundamentals to the
Python Programming language.
The materials in this booklet were developed to help students collaborate with each other in the
learning process and to become self-learners in an active learning environment. Students learn
programming concepts by doing programming and reflecting on the results of the activities that they
engage in.
Author: Lisa M. Olivieri, SSJ, Ph.D.
Name: _______________________________________ Partners: ________________________________ Python Activity 1: Flowcharts and Python
What is the relationship between a flowchart and a Python program?
Critical Thinking Questions:
1. What does the line of Python code in the Python program do? _________________________________________________________________________________
_________________________________________________________________________________
2. Circle equivalent representation of the Python code in the flowchart.
3. Execute following code. What output is produced?
a. print(Hello, my name is Pat!) ________________________________
b. print(Hello, my name is Pat) ________________________________
c. print(Hello.\nMy name is Pat) ________________________________
Learning Objectives
Students will be able to:
Content:
Explain how to display data in Python
Explain how to create a comment in Python
Determine the difference between a string literal and a number Process:
Create print statements in Python
Create Python code that displays results to calculated addition facts
Discuss problems and programs with all group members
Prior Knowledge
Understanding of flowchart output symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 1
Python Program Flowchart
Python Activity 1: Flowcharts and Python
4
4. Was there a problem with any of the sample code in question 3? If so, what caused the problem? ______________________________________________________________________________
______________________________________________________________________________
5. What caused the different output format for samples a and c in question 3? ______________________________________________________________________________
______________________________________________________________________________
6. What do you think the following Python statements output?
a. print(2+5) _________________________
b. print(2*5) _________________________
c. print(2+5) _________________________
d. print(Age:,20) _________________________
Enter the statements in the Python interpreter to verify your answers.
7. Examine the output for each statement in question 6. a. What is the difference in the output for the statements in a and c of question 6?
______________________________________________________________________________
b. What caused the difference? ____________________________________________________
______________________________________________________________________________
c. Which statements contain a string literal? ______________________________________________________________________________
______________________________________________________________________________
d. What does the comma (,) do in the print statement in part d of question 6? How does it affect the spacing of the output?
______________________________________________________________________________
______________________________________________________________________________
8. Examine the following code and its output. What do the first three lines of the program do?
______________________________________________________________________________
______________________________________________________________________________
Output
Python Activity 1: Flowcharts and Python
5
9. What would happen if you placed a # in front of the code: in the previous program?
______________________________________________________________________________
______________________________________________________________________________
Application Questions: Use the Python interpreter to design and check your work
1. Create a Python program containing three statements to implement the flowchart on the first page of this activity. Write the statements below.
2. Create one Python statement to produce the output expected from the flowchart. Be sure the output is printed on three lines.
3. Create a Python program containing two statements that prints the output to the right. Have the program calculate the answers to the two
arithmetic problems.
Python Activity 1: Flowcharts and Python
6
Notes and Questions Make note of any questions you have about Activity 1 on this page.
Name: _______________________________________ Partners: ________________________________ Python Activity 2: Input and Variables in Python How do you input and store data in a Python program?
Critical Thinking Questions:
1. Enter and execute the Python program. What is printed on the screen when the Python program is executed?
_________________________________________________________________________________
_________________________________________________________________________________
FYI: input() and print() are functions in Python.
2. Draw a line between each flowchart symbol and its corresponding Python code.
Learning Objectives
Students will be able to:
Content:
Explain how to input data in Python
Explain the meaning and purpose of a variable
Determine if a variable name is valid
Explain concatenation and the use of + Process:
Create input statements in Python
Create Python code that prompts the user for data and stores it in a variable
Create valid and good variable names
Prior Knowledge
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 2
Python Program
Flowchart Program
Python Activity 2: Input and Variables in Python
8
3. Examine the first line of Python program: name = input(What is your name? )
a. What happens when this line of code is executed?
______________________________________________________________________________
b. What appears on the screen when this line of code is executed?
______________________________________________________________________________
FYI: The words that appear on the screen to tell the user what to enter are known as a prompt.
c. What happens to the data when the user enters their name and presses the Enter button? That is,
where is their name stored?
______________________________________________________________________________
4. What happens when you execute each of the following lines of Python code?
a. name? = input(What is your name?)
______________________________________________________________________________
______________________________________________________________________________
b. your name = input(What is your name?)
______________________________________________________________________________
______________________________________________________________________________
c. 1st_name = input(What is your name?)
______________________________________________________________________________
______________________________________________________________________________
d. from = input(Where were you born?)
______________________________________________________________________________
______________________________________________________________________________
5. Examine the errors that occurred when executing the lines of code in question 5. Then examine the
following lines of valid code.
name2 = input(What is your name?) your_name = input(What is your name?)
yourName = input(What is your name?)
List the rules that need to be followed to create a valid variable name.
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
FYI: The word name in the Python code is a variable name given to a memory location used to store data.
Python Activity 2: Input and Variables in Python
9
6. Are the following variable names valid? Are they good names? Why or why not?
7. Execute the following lines of code. Is the output what you would expect? Why or why not?
_________________________________________________________________________________
_________________________________________________________________________________
8. Use the following set of Python statements to answer the questions below.
a. State the output for each of line of code.
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
b. Examine the first two print statements. How are they different? Does the difference affect the
output?
_________________________________________________________________________________
_________________________________________________________________________________
c. Notice that some statements include a comma (,) between the two literals being printed and some
statements use a +. Do they produce the same output? ____________________
d. Explain the purpose of the comma.
_________________________________________________________________________________
_________________________________________________________________________________
e. Why does the last print statement crash the program? What would you do to correct it?
_________________________________________________________________________________
_________________________________________________________________________________
Variable name Comments about variable name
price
costoffirstitem
Ic
firstName
FYI: + concatenates two strings. The strings can be string literals or a variable containing string literals.
Python Activity 2: Input and Variables in Python
10
9. State what is displayed on the screen when the following program is executed:
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
Application Questions: Use the Python Interpreter to input your code and check your work
1. State a good variable name for an employees ID number. ________________________________
2. Write a line of Python code that prompts the user for the name of their favorite ice cream and stores it
in a valid variable name. __________________________________________________________
3. Crazy Sentence Program. Create a program that prompts the user for the name of an animal, a color,
the name of a vehicle, and the name of a city. Then print a sentence that contains the user input in the
following order. Include the additional words in the sample output as part of your output. Example:
Assume the user enters the words: tiger, green, motorcycle, and Wildwood. The output would be:
The green tiger drove the motorcycle to Wildwood. _________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
Notes and Questions Make note of any questions you have about Activity 2 on this page.
Python Activity 3 Part A: Arithmetic Operations and Assignment Statements
11
Name: _______________________________________ Partners: ________________________________ Python Activity 3 Part A: Arithmetic Operations and Assignment Statements
Get the program to compute that! How do I assignment values to variables?
Critical Thinking Questions:
Python Program Flowchart Program
Learning Objectives
Students will be able to:
Content:
Explain each Python arithmetic operator
Explain the meaning and use of an assignment statement
Review string literals and print statements
Explain the use of + and * with strings and numbers
Use the int() and float() functions to convert string input to numbers for computation
Incorporate numeric formatting into print statements
Recognize the four main operations of a computer within a simple Python program Process:
Create input statements in Python
Create Python code that performs mathematical and string operations
Create Python code that uses assignment statements
Create Python code that formats numeric output
Prior Knowledge
Understanding of Python print and input statements
Understanding of mathematical operations
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 3
Python Activity 3 Part A: Arithmetic Operations and Assignment Statements
12
1. Execute the print statements in the Python program. What is the output for each statement? _________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
2. Draw a line between each flowchart symbol and its corresponding line of Python code.
3. Explain the purpose of each arithmetic operation: a. + ________________________________________________________________________
b. - ________________________________________________________________________
c. * ________________________________________________________________________
d. ** ________________________________________________________________________
e. / _______________________________________________________________________
f. // _______________________________________________________________________
g. % _______________________________________________________________________
FYI: An assignment statement is a line of code that uses a = sign. The statement stores the result
of an operation performed on the right-hand side of the sign into the variable memory location
on the lef0hand side.
4. Enter and execute the following two lines of Python code: age = 15 print(Your age is, age)
a. What does the assignment statement: age = 15 do?
______________________________________________________________________________
______________________________________________________________________________
b. What happens if you replace the comma (,) in the print statement with a plus sign (+) and execute
the code again? Why does this happen?
______________________________________________________________________________
______________________________________________________________________________
5. What is stored in memory after each assignment statement is executed?
Assignment Statement Computer Memory
answer = 6 ** 2 + 3 * 4 // 2 Answer
final = answer % 4 Final
Python Activity 3 Part A: Arithmetic Operations and Assignment Statements
13
6. What happens if you try to use the + with strings instead of numbers? Test the following program:
a. The third line of code contains an assignment statement. What is stored in fullName
when the line is executed?
______________________________________________________________________________
b. How can you fix the output so that the words are separated?
______________________________________________________________________________
c. What happens when you execute the following code? Why?
______________________________________________________________________________
______________________________________________________________________________
7. Before entering the following code into the Python interpreter, try to figure out what you think
the statement should print.
Now execute it. What does it do? Is this what you thought it would do?
______________________________________________________________________________
______________________________________________________________________________
8. Lets take a look at a program that prompts the user for two numbers and subtracts them. Execute the following code.
a. What output do you expect? _____________________________________________
b. What is the actual output? _____________________________________________
c. Revise the program in the following manner:
Between lines 2 and 3 add the following lines of code: num1 = int(firstNumber) num2 = int(secondNumber)
FYI: The + concatenates the two strings stored in the variables into one string. The assignment statement stored the results in the variable fullName. + can only be used when both operators are strings.
Python Activity 3 Part A: Arithmetic Operations and Assignment Statements
14
Next, replace the statement: difference = firstNumber secondNumber
with the statement: difference = num1 num2
Execute the program again. What output did you get? ________________________
d. Explain the purpose of the function int().
______________________________________________________________________________
______________________________________________________________________________
e. Explain how the changes in the program produced the desired output.
______________________________________________________________________________
______________________________________________________________________________
Application Questions: Use the Python Interpreter to check your work
1. Write the line of Python code that calculates and prints the answer to the following arithmetic
expressions:
a. 8 to the 4th power ___________________________________________________
b. The sum of 5 and 6 multiplied by the quotient of 34 and 7 using floating point arithmetic
_______________________________________________________________________
2. Write an assignment statement that stores the remainder obtained from dividing 87 and 8 in the
variable leftover
______________________________________________________________________________
3. Assume: courseLabel = CMSC courseNumber = 190
Write a line of Python code that concatenates the label with the number and stores the result in
the variable courseName. Be sure that there is a space between the course label and the course
number when they are concatenated. _________________________________________________________________
4. Create a program the outputs the total cost of a lunch order. Users should be prompted to input
the number of hamburgers, fries, and drinks they want and the program should print the total cost
of the order. The hamburgers cost 2.00, fries cost 1.50, and drinks cost 1.00. Be creative and
professional in prompting the user for the information and in displaying the output.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Name: _______________________________________ Partners: ________________________________ Python Activity 3 Part B: Arithmetic Operations and Assignment Statements
Get the program to compute that!
Critical Thinking Questions:
1. So far you have not been concerned about formatting output on the screen. Now you will discover
how Python allows a programmer to precisely format output. Some of the differences are very subtle,
so take notice of the differences in outputs.
Start by entering and executing the following code.
a. What is the problem with the manner in which the output is displayed?
_____________________________________________________________________________
______________________________________________________________________________
b. Replace the last line of code with the following: print("Total cost of laptops: %.2f" % price)
Discuss the change in the output.
_____________________________________________________________________________
______________________________________________________________________________
c. Replace the last line of code with the following: print("Total cost of laptops: $%.2f" % price)
Discuss the change in the output.
______________________________________________________________________________
______________________________________________________________________________
Learning Objectives
Students will be able to:
Content:
Incorporate numeric formatting into print statements
Recognize the four main operations of a computer within a simple Python program Process:
Create Python code that uses assignment statements
Create Python code that formats numeric output
Prior Knowledge
Understanding of Python print and input statements
Understanding of mathematical operations
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 3
Python Activity 3 Part B: Arithmetic Operations and Assignment Statements
16
d. Experiment with the number .2 in the print statement by substituting the following numbers and explain the results.
.4 ________________________________________________________________________
.0 ________________________________________________________________________
.1 ________________________________________________________________________
.8 ________________________________________________________________________
e. Now try the following numbers in the same print statement. These numbers contain a
whole number and a decimal. Explain the output for each number.
2.5 _______________________________________________________________________
8.2 _______________________________________________________________________
3.1 _______________________________________________________________________
f. Explain what the formatting code: %n.nf % variable does in a print statement where
n.n represents a number.
_____________________________________________________________________________
______________________________________________________________________________
g. Revise the print statement by changing the f to d and the decimal number to a whole number. Explain the sample formatting statements:
print("Total cost of laptops: %2d" % price) print("Total cost of laptops: %10d" % price)
______________________________________________________________________________
______________________________________________________________________________
h. Explain how %nd % variable formats numeric data. n represents a whole number.
______________________________________________________________________________
______________________________________________________________________________
2. Use the following program to answer the questions below.
FYI: Computers perform four main operations on data:
Input data into a computer
Output data to a screen or file
Process data using arithmetic, logical, searching or sorting operations
Store data
Python Activity 3 Part B: Arithmetic Operations and Assignment Statements
17
a. Using the code and comments in the program listed above, explain how the four main
operations are implemented in the program.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
b. There is one new concept exemplified in this sample program. What is it? From the
corresponding output, determine what it does.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Application Questions: Use the Python Interpreter to check your work
1. Write one line of Python code that will print the word Happy! one hundred times. ______________________________________________________________________________
2. Assume: itemCost = input(Enter cost of item: ) a. Write one line of code that calculates the cost of 15 items and stores the result in the
variable totalCost
________________________________________________________________________
b. Write one line of code that prints the total cost with a label, a dollar sign, and exactly two
decimal places. Sample output: Total cost: $22.50
________________________________________________________________________
3. Assume: height1 = 67850 height2 = 456
Use Python formatting to write two print statements that will produce the following output
exactly at it appears below:
______________________________________________________________________________
______________________________________________________________________________
4. You have already completed the following program in a previous activity. Format the output.
Create a program the outputs the total cost of a lunch order. Users should be prompted to input the
number of hamburgers, fries, and drinks they want and the program should print the total cost of the
order. The price of hamburgers is 2.00, fries is 1.50, and drinks is 1.00. Be creative and professional
in prompting the user for the information and in displaying the output.
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
Python Activity 3 Part B: Arithmetic Operations and Assignment Statements
18
Notes and Questions Make note of any questions you have about Activity 3 on this page.
Name: _______________________________________ Partners: ________________________________ Python Activity 4: Predefined Functions
How can I use the built-in code that is already part of Python?
Model 1: Predefined functions in Python
print(), round(), abs(), pow(), int(), etc. are known as predefined functions. Information that a function
needs to do its work is sent to the function between the parentheses (). This information is known as an
argument. To use a function, call the function. input(Enter your name) is a call to the input function sending the string Enter your name as an argument Critical Thinking Questions:
10. Circle the predefined functions in the following program.
11. Draw a line between each statement in the Python program and its corresponding statement in the flowchart.
Learning Objectives
Students will be able to:
Content:
Explain the purpose of a predefined function
Explain the functions: abs(), pow(), int() round(), random
Explain the math library functions: floor() and ceil()
Explain the use of the import statement
Explain the purpose of a function argument Process:
Write code that uses predefined functions
Prior Knowledge
Python concepts from Activities 1-3
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 4
Python Activity 4: Predefined Functions
20
12. Enter and execute the Python program on the previous page. a. What is the output for each statement ?
print(abs(-4.67)) _________________________
print(pow(5,3)) _________________________
print(pow(49,.5)) _________________________
print(int(34.8)) _________________________
print(round(6.9)) _________________________
import random print(random.randint(1,100)) ___________________
b. What is the difference between the round() function and the int() function?
______________________________________________________________________________
______________________________________________________________________________
4. What is the output for each line of code? Verify your answers by executing the code and explain the
answer given by the interpreter.
a. abs(4.5) _________________________________________________
b. int(678) _________________________________________________
c. round(-5.6) _________________________________________________
d. import random random.randint(4,10) ___________________________________________
What is the purpose of import random? What happens if you omit that line of code? ______________________________________________________________________________
______________________________________________________________________________
5. Write a definition of a predefined function.
______________________________________________________________________________
______________________________________________________________________________
6. Circle the argument in the following predefined function: number = 45.78 answer = round(number)
7. How many arguments can a function have? _______________________________________
8. answer = pow(4,3). What is/are the argument(s) in this code? ______________________
9. If a function contains more than one argument, do you think the order of the arguments makes a
difference? Explain your answer.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Python Activity 4: Predefined Functions
21
10. Execute the following code: import math x = 4.7
y = 5.3
z = -4.8
a = -3.2
print(math.ceil(x))
print(math.ceil(y)) print(math.ceil(z))
print(math.ceil(a))
print(math.floor(x))
print(math.floor(y))
print(math.floor(z))
print(math.floor(a))
a. Explain what the ceil() function does.
________________________________________________________________________
________________________________________________________________________ b. Explain the purpose of the floor() function.
________________________________________________________________________
________________________________________________________________________
c. Why are the calls to the math() and ceil() functions preceded by math.? ________________________________________________________________________
________________________________________________________________________
Application Questions: Use the Python Interpreter to check your work
1. Write a line of code that prints the integer portion of the number 21.45.
______________________________________________________________________________
2. Write code that prompts the user for a floating point number and prints the smallest integer that is
larger than the number the user entered.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
3. Write a line of code that prints a random number between one and 6.
______________________________________________________________________________
______________________________________________________________________________
4. Assume that a user enters any number and that the number is stored in the variable userNumber.
Write a line of code that converts the input to a float. Then write a line of code that prints the
positive value of the users input. ______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
5. Write a line of code that calculates the square root of 900 and stores the result in the variable
answer. ______________________________________________________________________________
Python Activity 4: Predefined Functions
22
Notes and Questions Make note of any questions you have about Activity 4 on this page
Name: _______________________________________ Partners: ________________________________ Python Activity 5: Boolean Expressions and Selection Statements
True or False and making choices
Model 1: Programming Structures
Sequence Structure Decision or Branching Structure
Looping Structure
Critical Thinking Questions:
1. Each of the flowchart symbols in the chart above represents lines or segments of code. After
examining the chart, write a description of:
a. sequence structure ________________________________________________________
________________________________________________________________________
b. decision or branching structure _____________________________________________
_______________________________________________________________________
c. looping structure ____________________________________________________
________________________________________________________________________
Learning Objectives
Students will be able to:
Content:
Explain the three types of programming structures
Explain how conditional operators and logical operators are used in programming
Use conditional operators with strings and numeric values
Implement the Python syntax of an if/else statement
Determine good test data for programs that include if/else statements Process:
Write code that includes if statements and if/else statements
Write correct Boolean expressions and compound expressions
Prior Knowledge
Python concepts from Activities 1-4
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 5
Python Activity 5: Boolean Expressions and Selection Statements
24
2. Which structure best describes the types of Python programs you have written so far? Do you
think this structure is the best structure to use for all programs? Why or why not?
______________________________________________________________________________
______________________________________________________________________________
3. Which structure allows the programmer to create code that decides what code is executed?
_____________________________________________________________________________
Model 2: Conditional Operators
Conditional operators, also known as relational operators, are used to compare the relationship
between two operands. Expressions that can only result in one of two answers are known as
Boolean expression.
4. Determine the meaning of each of the following conditional operators.
If you are not sure of the meaning of any symbol, create some example
expressions, type them into the Python interpreter (see figure to the
right) and examine the results.
a. < ___________ b. > ____________
c. = ____________
e. != ___________ f. == ____________
5. What is the result of each of the following expressions?
Assume x = 4, y = 5, z = 4
a. x > y ______________________________________
b. x < y ______________________________________
c. x == y ______________________________________
d. x != y ______________________________________
e. x >= z ______________________________________
f. x 2 * x ______________________________________
h. y * x z != 4 % 4 + 16 ______________________________________
i. pow(x,2) == abs(-16) ______________________________________
6. What is the result of the following expressions?
Assume word1 = hello, word2 = good-bye
a. word1 == word2 ______________________________________
b. word1 != word2 ______________________________________
c. word1 < word2 ______________________________________
d. word1 >= word2 ______________________________________
Python Activity 5: Boolean Expressions and Selection Statements
25
7. Explain how the conditional operators are used when the operands are strings.
______________________________________________________________________________
______________________________________________________________________________
8. There are only two possible answers to the expressions in questions 5 and 6. What are they?
_______________________________________________________________________________
9. What is the Python code equivalent of the diamond flowchart symbol in the program above?
________________________________________________________________________
10. Enter and execute the following code. Use various values for the original cost and the sale price.
Explain what the following lines of code do. Each line appears in the program above.
a. originalPrice = int(originalPriceString)
________________________________________________________________________
b. percentOff =(originalPrice - salePrice)/originalPrice * 100
________________________________________________________________________
c. print("Sale price: $%.2f" %salePrice)
________________________________________________________________________
d. print("Percent off: %2d" % percentOff + "%")
________________________________________________________________________
e. if percentOff >= 50: print("You got a great sale!")
________________________________________________________________________
Model 3: IF/ELSE Statement
Flow chart Python Program
Python Activity 5: Boolean Expressions and Selection Statements
26
11. Revise the program in #10. If the percent off is 50% or more print Congratulations! in addition to what is already printed. Use a second print statement to do this. Write the code for this part
of the program.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
12. Revise the program in #12 so that it prints Done! when the program is complete no matter what the percent off is. How does the placement of this line of code differ from the placement of
the code created for #12?
______________________________________________________________________________
______________________________________________________________________________
Python Program
Flowchart
13. Compare the flowchart above with the corresponding Python Program. Carefully compare if/else
statement in the two programs. Enter and execute the Python program above.
a. Test the program at least three times. List the three test data you used and the
corresponding output. Explain why they were the best data to use as a test for the
program.
___________________ __________________ ___________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Python Activity 5: Boolean Expressions and Selection Statements
27
b. Now you want to add another print statement to the Python program above so that it
printed Thats really hot! when the water is 212 degrees or hotter. Rewrite the code below with this statement included.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
FYI: We can use logical operators to determine logic between conditions (relational expressions).
14. Sometimes you want to test more than one condition to determine which code segment should be
executed. You can use the following logical operators to create compound conditions. Examine
each operator and a sample of its use. Provide an explanation of how each operator works.
Operator Example Explanation
and (age >= 17) and (hasLicense = = true)
or (cost < 20.00) or (shipping = = 0.00)
not not (credits> 120)
15. Assume the value of the variable numBooks is 40. State the values of each of the Boolean
expression.
Expression Value
(numBooks > 5) and (numBooks < 100)
(numBooks < 5) or (numBooks > 100)
not(numBooks * 10 == 100)
16. Suppose you want to determine if a student is ready to graduate. The 3 criteria for graduation are
that the student has earned at least 120 credits, their major GPA is at least 2.0 and their general
GPA is also at least 2.0.
Missing Boolean expression
Python Activity 5: Boolean Expressions and Selection Statements
28
Which Boolean expression would be the correct test for Python code?
a. numCredits >= 120 or majorGPA >= 2.0 or overallGPA >= 2.0
b. numCredits > 120 and majorGPA > 2.0 or overallGPA > 2.0
c. numCredits > 119 and majorGPA >= 2.0 and overallGPA >= 2.0
d. numCredits >= 120 and majorGPA >= 2.0 and overallGPA >= 2.0
17. Enter and execute the program in #16. Include your choice for the correct Boolean expression.
Create several data sets to test all possibilities for the Boolean expression. List the data you used
to test all possibilities for the expression.
Data Set numCredits majorGPA overallGPA Expression Result (True or False)
1
2
3
4
5
6
7
8
9
10
Application Questions: Use the Python Interpreter to check your work
1. Write a Boolean expression that tests if the value stored in the variable num1 is equal to the value
stored in the variable num2.
______________________________________________________________________________
2. Write a Boolean expression that tests if the value stored in the variable time is less than the value
stored in the variable maxTime or if the value stored in the variable cost is less than the value
stored in the variable maxCost
______________________________________________________________________________
3. Write the code for an if statement that adds 5 to the variable num1 if the value stored in the
variable testA equals 25. Otherwise subtract 5 from num1.
______________________________________________________________________________
4. Write the code for an if statement that prints a random number between one and 6 if the value
stored in the variable isValid equals the Boolean value true.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Python Activity 5: Boolean Expressions and Selection Statements
29
5. Write a Python program that prompts the user for the cost of two items to be purchased. Then
prompt the user for their payment. If they enter an amount that is less than the total cost of the
two items, print a message that tells them how much they still owe. Otherwise, print a message
that thanks them for their payment and tells them how much change they will receive.
Thoroughly test your code for all possible input.
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6. Write a Python program that prompts the user for a word. If the word comes between the words
apple and pear alphabetically, print a message that tells the user that the word is valid, otherwise,
tell the user the word is out or range.
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7. Write a Python program that prompts the user for a multiple of 5 between 1 and 100. Print a
message telling the user whether the number they entered is valid.
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Python Activity 5: Boolean Expressions and Selection Statements
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Notes and Questions Make note of any questions you have about Activity 5 on this page.
Name: _______________________________________ Partners: ________________________________ Python Activity 6: Functions
Modularizing your code
Critical Thinking Questions:
Python Program
Flowchart
Learning Objectives
Students will be able to:
Content:
Explain the meaning and purpose of a function
Recognize a function definition, function header, and function call in a program
Combine the use of functions with if/else statements
Explain programs that use the same function multiple times
Use good test data for programs that include functions Process:
Write code that includes function definitions and function calls
Write programs that incorporate functions and if/else statements
Prior Knowledge
Python concepts from Activities 1-5
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 6
Python Activity 6: Functions
32
FYI: A function is a segment of code that performs a single task.
1. Closely examine the flowchart and Python program above.
a. Draw arrows between each flowchart symbol and the equivalent Python code.
FYI: A function definition is the segment of code that tells the program what to do when the
function is executed. The first line of a function definition is known as the function
header
b. What Python keyword is used to indicate that a code segment is a function definition?
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c. What is the function header in the Python code above?
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d. The name of the function is in the function header. What is the name of the function?
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e. Examine the Python function. Explain the syntax required for a function: indentation,
etc.
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f. Enter and execute the Python program. What is the output?
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g. What line of code would you add to the program to print the last two lines twice? Where
would you add the code?
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2. Examine the following program
a. Label the function definition and the function call.
b. The function call and the function definition each include a variable within the
parentheses. The variable in this role is known as an argument. What is the argument in
the function definition? What is its purpose?
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Python Activity 6: Functions
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c. In this example the argument in the function definition and the argument in the function
call have the same name. Is this required? _______________________________
d. Enter and execute the program. Verify your answer to question c by changing the variable name in the main program from radius to number. Do not change the variable
name in the function definition. Does the program still work? __________________
e. Write a line of code that calls the calculateArea function and sends the value 6 as the argument. Add the line of code to the main program and execute it to be sure it works
properly. _______________________________________________________________
f. Add a second function to the program that calculates and prints the diameter of a circle,
given the radius as an argument (parameter). Place the function definition above the main
part of the program. Write the function below.
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g. Add another line of code to the main part of the program that calls the function that was
created in part f. Send the radius entered by the user as the argument to the function. ________________________________________________________________________
3. What is the purpose of a function? Why do programmers use them?
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4. Carefully examine the following program.
a. What is the first line of code executed by the Python interpreter?
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Python Activity 6: Functions
34
b. Enter and execute the program. Use the following test data and indicate what the output
is for each set of data.
Data Set Operand 1 Operand 2 Operator Result
1 2 6 +
2 3 8 -
3 34 23 +
4 4 5 /
c. What problems did you notice when you entered Data Sets 3 and 4?
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d. Add code to the program that would warn the user about the problems that could occur
when data similar to that in Data Sets 3 and 4 are entered. See sample output below. List
the lines of code below the sample output.
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Python Activity 6: Functions
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FYI: So far, the functions you have printed any results within the function. They did not send
back any information to the original calling code. Functions that do not send back
information to where they are called are known as void functions. Functions often send
back or return the result and are known as value returning functions.
5. Enter and execute the code below. Carefully examine the code.
a. What is the new keyword used in the function definition? What do you think the
keyword tells the program to do?
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b. Write the line of code from the program that includes the function call to getSmaller.
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c. In a void function, the function call is on a line by itself. Why is this function call
placed on the right-hand-side of an assignment statement?
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d. What are the arguments used for the function call? _______________________________
6. Examine the following Python program.
a. What does the program do?
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b. Circle the function call. What is different about the placement of the function call?
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Python Activity 6: Functions
36
c. Is the function a void function or a value returning function? ____________________
d. Why is the import statement needed in this program?
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7. The following Python program performs the same operations and produces the same output as the
previous program. Describe the major differences between the two programs. Edit the previous
program so that it looks like this one and execute it.
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Application Questions: Use the Python Interpreter to check your work
1. Write a function that draws a frog. Call the function to be sure it works. Sample frog:
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Python Activity 6: Functions
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2. Expand the program in #1 to produce the following output.
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3. Write a Python program that prompts the user for three words and prints the word that comes last
alphabetically. Use a function to create the program.
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Python Activity 6: Functions
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Notes and Questions Make note of any questions you have about Activity 6 on this page.
Name: _______________________________________ Partners: ________________________________ Python Activity 7: Nested IF/ELSE Statements
Decisions, decisions decisions within decisions!
Critical Thinking Questions:
1. Closely examine the flowchart and Python program above.
Learning Objectives
Students will be able to:
Content:
Explain the purpose of a nested if-else statement
Explain how to use Python if-elif structure
Explain how to test code using Python if-elif structure Process:
Write code that includes if-elif statements
Write code that uses if-elif statements and functions
Prior Knowledge
Python concepts from Activities 1-6
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 7
Python Program
Flowchart
Python Activity 7: Nested IF/ELSE Statements
40
a. Draw arrows between each flowchart symbol and the equivalent Python code.
b. In the Python code, circle the if/else statement that is nested within another if/else statement.
c. Enter and test the code. List five numbers that you would use to test this program. Indicate why you chose the numbers.
Number Why chosen
2. Enter and execute the following Python program using the same data as you used for #1c.
a. How does the output for this program compare with the output for the previous program? ___________________________________________________________________________
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b. What new keyword is used in this program? _______________________________________
c. Notice the syntax of this program compared to the previous program. Which program contains simpler indentation? _____________________________________________
FYI: elif is the Python keyword that represents else if and allows you to test for one of several options. As
soon as one of the tests is true, the rest are ignored.
d. You can use elif as many times as you need to. Suppose you wanted to add the comment Good! for grades that are between 80 and 89. Where would you add it? Write the code for this additional choice.
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e. Does the placement of an additional elif clause matter? ______________________________
f. When is the code associated with the else statement executed? ___________________________________________________________________________
Python Activity 7: Nested IF/ELSE Statements
41
g. Describe how an if/elif/else statement works. ___________________________________________________________________________
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h. Change the program in #2 so that it prints the following messages. Write the code below.
Greater than 90 Very Good!
Between 80 and 89 Good!
Between 70 and 79 Satisfactory
Between 60 and 69 Fair
Less than 60 Poor
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i. Make a final change to the program so that it prints an error message if the grade entered
is greater than 100 or less than 0.
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3. Is the use of the else statement mandatory when creating an if/elif statement? Explain your answer.
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Python Activity 7: Nested IF/ELSE Statements
42
Application Questions: Use the Python Interpreter to check your work
1. Write an if/elif statement that assigns a value to the variable bonus depending on the amount of sales. Assume the amount of the sales is stored in a variable called sales.
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2. Carefully examine and then complete the following Python program. The program prompts the user to enter a number between 1 and 5 and also generates a random number between 1 and 5. The
program prints the number the user enters and prints the random number. The program then
compares the two numbers. If the numbers are the same, it prints the message You picked the same number as the computer!. If the number the user entered is higher than the random number, the program should print Your number is higher than the computers number. Otherwise, it should print: Your number is smaller than the computers number.
Explain what the if/else statement does in the Main Program.
Sales Bonus
>= 100,000 10,000
>= 75,000 5,000
>= 50,000 2,500
>= 25,000 1,000
Python Activity 7: Nested IF/ELSE Statements
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.
Python Activity 7: Nested IF/ELSE Statements
44
Notes and Questions Make note of any questions you have about Activity 7 on this page.
Name: _______________________________________ Partners: ________________________________ Python Activity 8: Looping Structures WHILE Loops
Repeating code
Critical Thinking Questions
1. Closely examine the flowchart and Python program below.
FYI: A looping structure allows a block of code to be repeated one or more times. A while loop is
one of the two looping structures available in Python.
Python Program
Flowchart
a. Draw arrows between each flowchart symbol and the equivalent Python code.
b. In the Python code, circle all the code associated with the WHILE loop.
Learning Objectives
Students will be able to:
Content:
Explain the three parts of a loop
Explain the syntax of a while loop
Explain sentinel-controlled and counter controlled loops
Explain short-cut operators Process:
Write code that includes sentinel-controlled and counter controlled loops
Write code that uses short-cut operators
Prior Knowledge
Python concepts from Activities 1-7
Understanding of flowchart input symbols
Further Reading
Transitioning from Visual Logic to Python: Chapter 8
Python Activity 8: Looping Structures WHILE Loops
46
c. Enter and test the code. What does the line of code: x=x+1 do?
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d. How does the Python interpreter know what lines of code belong to the loop body?
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e. Every loop structure requires three actions. Identify the line of code in the Python
program that corresponds to each of the three actions.
Initialize a variable used in the test condition:
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Include a test condition that causes the loop to end when the condition is false:
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Within the loop body, update the variable used in the test condition:
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2. Enter and execute the following code.
a. Beside each line of code below explain what the code does.
b. Explain the difference between the two print statements.
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3. The following code should print the numbers from 1 to 10, but it does not print anything.
Correct the problem.
number = 12 while number
Python Activity 8: Looping Structures WHILE Loops
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b. What caused the output to be what it was?
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c. Does the program end? Why or why not? ________________________________
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6. Enter and execute the following code: number = 1
while number
Python Activity 8: Looping Structures WHILE Loops
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f. How many times does the loop execute? ______________________________________
FYI: A looping structure for which you know the number of times it will execute is known as a
count-controlled loop.
8. Sometimes a programmer does not know how many times data is to be entered. For example,
suppose you want to create a program that adds an unspecified amount of positive numbers
entered by the user. The program stops adding numbers when the user enters a zero or a negative
number. Then the program prints the total. Before creating this program, review the three actions
required for all loops:
a. Initialize a variable that will be used in the test condition: What will be tested to
determine if the loop is executed or not? Write a line of code that initializes a variable to
be used in the test condition of the loop for this program. The variable should contain a
value entered by the user.
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b. Include a test condition that causes the loop to end when the condition is false: What is
the test condition for the while loop used in this program?
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c. Within the loop body, update the variable used in the test condition: Write the code for
the loop body. Include the code to update the variable in the test condition.
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d. Is this a count-controlled loop? Why or why not?
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e. Complete the program. Enter and execute the code. Does it work properly? __________
FYI: Short-cut operators provide a concise way of creating assignment statements when the
variable on the left-hand side of the assignment statement is also on the right-hand side. The
addition short-cut operator (+=) is usually used for incrementing a variable.
9. Enter and execute the following code: number = 1 number += 3
print(number)
a. What does the += shortcut operator do? ________________________________________________________________________
b. The code: x += 5 is equivalent to which of the following lines of code?
x = 5
x = y + 5
x = x + 5
y = x + 5
Python Activity 8: Looping Structures WHILE Loops
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c. Replace the operator += with the following shortcut operators and execute the code. Explain what each operator does.
-= _________________________________________________________
*= _________________________________________________________
10. Enter and execute the following code: bonus = 25 salary += bonus print(Total salary:, salary)
a. What is the output of the preceding code? Is it what you expected?
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b. Edit the code so that it produces valid output.
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c. As a result of correcting this code segment, what is needed in order for the shortcut
operators to work properly?
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d. Is the following line of code valid: 23 += total? Why or why not?
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11. The following code should print the numbers beginning at 100 and ending with 0. However it is
missing a line of code. Add the missing code, using the shortcut operator. Indicate where the
code belongs. countdown = 100 while countdown > 0: print(countdown)
print(Done!)
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12. Enter and execute the following code: doAgain = "y"
while doAgain == "y":
word = input("Enter a word:")
print("First letter of " + word + " is " + word[0])
doAgain = input("Type y to enter another word and anything
else to quit.")
print("Done!")
a. What does the program do?
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b. What is the name of the variable used to store the users input? ____________________
c. In the print statement, what does word[0]represent? ___________________________
Python Activity 8: Looping Structures WHILE Loops
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d. If you changed 0 to 1 in word[0]in the print statement above, what is printed?
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e. When does the program end? _____________________________________________
g. Why is the loop in this program is an example of a sentinel control loop?
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h. Examine the print statement in this program: print("First letter of " + word + " is " + word[0])
What is the purpose of the + as part of the argument in the print statement? What happens if you replace the + with a ,? ________________________________________________________________________
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13. Examine the code below. name = Simone
cost = 3.56
numApples = 89
What type of data is stored in each variable: (integer, floating point, or string)
name __________________________
cost __________________________
numApples __________________________
FYI: A variable that can store only the values True and False is called a Boolean variable.
14. Given the assignment statement: foundCost = False
What value is stored in the variable foundCost? ________________________________
What type of data is stored in foundCost? ________________________________
15. Enter and execute the following code:
a. What type of variable is doAgain? _______________________________________
FYI: A sentinel-controlled while loop is a loop that repeats the loop body until the user enters a pre-
specified value.
Python Activity 8: Looping Structures WHILE Loops
51
b. What does the program do?
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c. What does the following line of code do? maxNum1 = max(num1, num2, num3, num4)
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d. Experiment with the arguments in the max() function in the program to determine if the
function must have four arguments. Demonstrate your answer.
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e. What does the following code in the program do? if another != 'y':
doAgain = False
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Application Questions: Use the Python Interpreter to check your work
1. Write a code segment that prompts the user for an even number. As long as the number is
not even, the user should be given a message and prompted again for an even number.
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2. Write code segment that prompts the user for a letter from a-z. As long as the character is not between a-z, the user should be given a message and prompted again for a letter between a-z. ______________________________________________________________________________
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3. Complete the following program:
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Python Activity 8: Looping Structures WHILE Loops
52
Notes and Questions Make note of any questions you have about Activity 8 on this page.
53
Name: _______________________________________ Partners: ________________________________ Python Activity 9: Looping Structures: FOR Loops
Another form of loops
Critical Thinking Questions:
4. Enter and execute the following two Python programs.
WHILE LOOP -- Python Program
FOR LOOP Python Program
a. What is the output for each program?
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b. Both programs produce the same output. Which code fragment is more concise?
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FYI: The Python predefined range() function is used to define a series of numbers and can be used in
a FOR loop to determine the number of times the loop is executed..
2. Enter and execute