Baabtra.com little coder chapter - 5

Little Coder Program

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What you’ve learned?

Doing simple drawings using turtle module

Making DecisionsChapter 5

• We know Computer program lets a computer follow instructions,

but so far the computer doesn't know how to make decisions.

Making Decisions

• We know, among this 4 animals one is not like others

• But computer can’t compare them unless we give instruction for

that

• With the "if" instruction, a computer can compare two things and

make a decision

Making Decisions

• Consider the below example

“We might ask, “Are you older than 20?” and if the answer is yes,

respond with “You are too old!”

These sorts of questions are called conditions, and we combine these

conditions and the responses into if statements.

Making Decisions

Example

>>>age=13

>>>if age > 20:

print(“You are too old”)

print('Why are you here?')

print(“Okey, We may continue”);

Example

>>>age=13

>>>if age > 20:

print(“You are too old”)

print('Why are you here?')

print(“Okey, We may continue”);

These instruction will

execute only if the age is

greater than 20

Example

>>>age=13

>>>if age > 20:

print(“You are too old”)

print('Why are you here?')

print(“Okey, We may continue”);

These empty space is important.

Code that is indented the same

number of spaces from the left

margin is grouped into a block, and

whenever you start a new line with

more spaces than the previous

one, you are starting a new block

that is part of the previous one,

like this

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Block 1

Block 2

Block 3

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Block 1

Block 2

Block 3

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Block 1

Block 2

Block 3

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Line of code

Block 1

Block 2

Block 3

Try this !

• Write down a simple python program to store your marks in 3

subjects, and calculate the average mark. If the average mark is

greater than 90, print “You are an excellent student” and “Keep up

the good work”

Try this !

>>>markInMaths=80

>>>markInScience=90

>>>markInLanguage=90

>>>averageMark=(markInMaths+markInScience+markInLanguage)/3

>>>if averageMark > 90:

print(“You are an excellent Student !!”)

print(‘Keep up the good work')

IF then Else statements

Consider the example

• You know where ever there is an if, there are possibilities of an

else too.

NO Yes

Mark=80

If mark>90

Print “Excellent!!”

Print “Try to improve”

Consider the example

• You know where ever there is an if, there are possibilities of an

else too.

NO Yes

Mark=80

If mark>90

Print “Excellent!!”

Print “Try to improve”

We’ve declare a variable mark with value=80

Consider the example

• You know where ever there is an if, there are possibilities of an

else too.

NO Yes

Mark=80

If mark>90

Print “Excellent!!”

Print “Try to improve”

Checking whether the value of mark is greater than 90 or not

Consider the example

• You know where ever there is an if, there are possibilities of an

else too.

NO Yes

Mark=80

If mark>90

Print “Excellent!!”

Print “Try to improve”

As mark is less than 90, it will print “Try to improve”

Consider the example

• You know where ever there is an if, there are possibilities of an

else too.

NO Yes

Mark=92

If mark>90

Print “Excellent!!”

Print “Try to improve”

Now We’ve changed the value of mark into 92

Consider the example

• You know where ever there is an if, there are possibilities of an

else too.

NO Yes

Mark=92

If mark>90

Print “Excellent!!”

Print “Try to improve”

Again checking whether the value of mark is greater than 90 or not

Consider the example

• You know where ever there is an if, there are possibilities of an

else too.

NO Yes

Mark=92

If mark>90

Print “Excellent!!”

Print “Try to improve”

As its greater than 90, it will print “Excellent”

Example

>>>markInMaths=80

>>>markInScience=90

>>>markInLanguage=90

>>>averageMark=(markInMaths+markInScience+markInLanguage)/3

>>>if averageMark > 90:

print(“You are an excellent Student !!”)

>>> else

print(“Try to Improve”)

>>> print("Want to hear a dirty joke?")

Want to hear a dirty joke?

>>> age = 12

>>> if age == 12:

print("A pig fell in the mud!")

else:

print("Shh. It's a secret.")

Another Example

if and elif Statements

if and elif

• If and elif is used whenever we want to give a condition with else

NO Yes

Mark=50

If mark>90

Print “Excellent!!”

Print “Try to improve”

Else If mark>60

Yes

Print “Poor”

NO

if and elif

• If and elif is used whenever we want to give a condition with else

NO Yes

Mark=50

If mark>90

Print “Excellent!!”

Print “Try to improve”

Else If mark>60

Yes

Print “Poor”

NO

Checking with else condition

Example>>>markInMaths=80

>>>markInScience=90

>>>markInLanguage=90

>>>averageMark=(markInMaths+markInScience+markInLanguage)/3

>>>if averageMark > 90:

print(“You are an excellent Student !!”)

>>> elif averageMArk>60

print(“Try to Improve”)

>>>else

print(“Poor”)

>>> age = 12

>>> if age == 10:

print("What do you call an unhappy cranberry?")

print("A blueberry!")

elif age == 11:

print("What did the green grape say to the blue grape?")

print("Breathe! Breathe!")

elif age == 12:

print("What did 0 say to 8?")

print("Hi guys!")

else:

print("Huh?")

What did 0 say to 8? Hi guys!

Another Example

Combining Conditions

Example

>>> if age == 10 or age == 11 or age == 12 or age == 13:

print('What is 13 + 49 + 84 + 155 + 97? A headache!')

else:

print('Huh?')

>>> if age >= 10 and age <= 13:

print('What is 13 + 49 + 84 + 155 + 97? A headache!')

else:

print('Huh?')

Exercise !

Exercise !

• Create an if statement that checks whether the amount of money contained

in the variable money is between 100 and 500 or between 1,000 and 5,000.

Print a message accordingly

• Create an if statement that prints the string “I can buy too many things” if

the variable money contains a number that’s greater than 500, prints “I

can’t buy toys” if it’s less than 300, and prints “I can buy some chocolates”

if it’s less than 100.

End of Chapter 5