List vs IEnumerable vs IQueryable vs ICollection vs IDictionary - CodeProject

/LVWYV,(QXPHUDEOHYV,4XHU\DEOHYV,&ROOHFWLRQYV,'LFWLRQDU\&RGH3URMHFW

KWWSZZZFRGHSURMHFWFRP$UWLFOHV/LVWYV,(QXPHUDEOHYV,4XHU\DEOHYV,&ROOHFWLRQY"GLVSOD\ 3ULQW

0DKVD+DVVDQNDVKL)HE &32/

/LVWYV,(QXPHUDEOHYV,4XHU\DEOHYV,&ROOHFWLRQYV,'LFWLRQDU\

7KLVDUWLFOHLVRQHRIWKHILUVWVRXUFHVZLWKFRPSOHWHDQGFOHDUFRPSDULVLRQDERXWGDWDVWUXFWXUH$UUD\$UUD\/LVW/LVW,/LVW,&ROOHFWLRQ6WDFN4XHXH+DVK7DEOH'LFWLRQDU\,4XHU\DEOH,(QXPHUDEOH

,/LVWYV,(QXPHUDEOHYV,4XHU\DEOHYV,&ROOHFWLRQYV,'LFWLRQDU\.%

'HPR)RU'DWD$FFHVV/D\HU

&ROOHFWLRQ

YRWHV



&ROOHFWLRQLVVHWRIUHODWHGUHFRUGV,WLQFOXGHVDPHDQLQJIXOXQLW:HVKRXOGVHOHFWDSSURSULDWHFRQWDLQHUWRVWRUHGDWDWHPSRUDULO\IRUIHWFKDQGPRGLILFDWLRQSURFHVV$SSURSULDWHFRQWDLQHUGHSHQGVRQ2XUDLPZKLFKZHZDQWWRGRRQGDWDMXVWUHDGLQJGRLQJPRGLILFDWLRQVXFKDVLQVHUWGHOHWHXSGDWH1XPEHURIUHFRUGVZKLFKVKRXOGEHWUDQVIHUUHG

$UUD\)L[HG/HQJWK!,WVVL]HLVQRWIOH[LEOH,WLVGHWHUPLQHGDWLQVWDQWLDWLRQWLPH

6WURQJO\7\SHG!'HYHORSHUVGHWHUPLQHLWVW\SHDWWKHLQVWDQWLDWLRQWLPHLQVWHDGRIUXQWLPH7KLVIHDWXUHPDNHVWRUXQIDVWDWUXQWLPHVLQFHLWGRHVQRWQHHGWRZDLWIRUW\SHGHILQLWLRQ'HYHORSHUVXVHIRUHDFKNH\ZRUGWRILOODQGLWHUDWHWKURXJKDUUD\

)L[HG/HQJWKDQG6WURQJO\7\SHGFRQVXPHOHVVPHPRU\WKHUHIRUHLWKDVJRRGSHUIRUPDQFH

$UUD\/LVW



$UUD\OLVWLV127)L[HG/HQJWK!,WLVSRVVLEOHWKDWGDWDJURZV2QWKHRQHKDQGLWLVDJRRGIHDWXUHZKHQHYHUGHYHORSHUVDUHQRWVXUHDERXWVL]HRIDUUD\OLVWDQGRQWKHRWKHUKDQGLWPLJKWWDNHORQJWLPHIRUVL]HGHILQLWLRQ

$UUD\OLVWLV1276WURQJO\7\SHG!:KHQHYHUGHYHORSHUVDUHQRWVXUHDERXWZKDWLVH[DFWO\W\SHGHILQLWLRQIRULQSXWRURXWSXWGDWDDQGWKH\VKRXOGZDLWXQWLOUXQWLPHWRDSSHDULWVW\SH,WVGLVDGYDQWDJHLVWLPHFRQVXPLQJDWWKHUXQWLPHIRUPHPRU\WRGHWHUPLQHW\SHGHILQLWLRQ

'HYHORSHUVXVHIRUHDFKNH\ZRUGWRILOODQGLWHUDWHWKURXJKDUUD\OLVW

$UUD\/LVWFDQDFFHSWVWULQJLQWHJHUDQGGHFLPDO6LPXOWDQHRXVO\



+DVK7DEOH+DVK7DEOHLVDQRWKHUNLQGRIGDWDVWUXFWXUHWKDWGHILQHVNH\YDOXHIRUHDFKGDWDVHFWLRQ7KHUHIRUHILQGLQJGDWDLVHDV\MXVWE\SRLQWRXWWRLWVNH\,WLV127VWURQJO\W\SHGDQG127IL[HGVL]H



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

,WLV127VWURQJO\W\SHGDQG127IL[HGVL]H

6WDFN3XVK



6WDFN3RS

4XHXH4XHXHLVDQRWKHUNLQGRIGDWDVWUXFWXUHWKDWGHILQHVSULRULW\IRUHDFKLWHPLQRWKHUIRUP7KHUHIRUHZKHQHYHU\RXZDQWWRLQVHUWLWHP\RXVKRXOGDGG(QTXHXHLWDWWKHKHDGRIWKHTXHXHDQGZKHQHYHU\RXZDQWWRUHPRYH'HTXHXHLWHPIURPTXHXH\RXVKRXOGUHPRYHLWIURPERWWRPRIWKHTXHXH$V\RXJRWLWLWHPWKDWFRPHVILUVWRQHZLOOEHVHOHFWHGWR'HTXHXHIRUILUVWRQHDQGLWVH[SUHVVLRQLQFRPSXWHUVFLHQFHLVHTXDOWR)LUVWLQ)LUVWRXW ),)2

,WLV127VWURQJO\W\SHGDQG127IL[HGVL]H

4XHXH(QTXHXH

4XHXH'HTXHXH



/LVW:K\ZHQHHG/LVW"

/LVWLV127)L[HG/HQJWK!,WLVSRVVLEOHWKDWGDWDJURZV2QWKHRQHKDQGLWLVDJRRGIHDWXUHZKHQHYHUGHYHORSHUVDUHQRWVXUHDERXWVL]HRIDUUD\OLVWDQGRQWKHRWKHUKDQGLWPLJKWWDNHORQJWLPHIRUVL]HGHILQLWLRQ

/LVWLV6WURQJO\7\SHGZKHQLWLVGHILQHG*HQHULF!:KHQHYHUGHYHORSHUVDUHVXUHDERXWZKDWLVH[DFWO\W\SHGHILQLWLRQIRULQSXWRURXWSXWGDWDDQGWKH\GRQRWZDLWXQWLOUXQWLPHWRDSSHDULWVW\SH7KLVIHDWXUHPDNHVWRUXQIDVWDWUXQWLPHVLQFHLWGRHVQRWQHHGWRZDLWIRUW\SHGHILQLWLRQ

'HYHORSHUVXVHIRUHDFKNH\ZRUGWRILOODQGLWHUDWHWKURXJKDUUD\

6LQFH/LVWLVQRW)L[HG/HQJWKPDNHVGHYHORSHUVIHHOIOH[LEOHWRXVHLWDQGEHFDXVHRILWLV6WURQJO\7\SHGZKHQLWLVGHILQHG*HQHULFVRRXUFRGHUXQVIDVWDWUXQWLPHEHFDXVHLWGRHVQRWQHHGWRZDLWIRUW\SHGHILQLWLRQ



,/LVW:K\ZHQHHG,/LVW",/LVWLVLPSOHPHQWHGE\/LVW,OLVWLVDQLQWHUIDFHDQGLPSOHPHQWVPHWKRGV:KHQHYHU\RXHVWLPDWHSUREDELOLW\WKDW\RXUFRGHZRXOGEHFKDQJHGLQIXWXUH\RXKDYHWRXVH,/LVWEHFDXVHLQWHUIDFHUHGXFHVGHSHQGHQF\DQGZLWKWKHOLWWOHPRGLILFDWLRQ\RXUFRGHUXQV7KHUHIRUH\RXVKRXOGREVHUYHSRO\PRUSKLVPLQRUGHUWRGHFRXSOH\RXUDSSDQGFRQWURORQDGGLQJRUUHPRYLQJPHWKRGWKDWPLJKWEHFKDQJHG(YHU\WKLQJHOVHLVVLPLODU:KHQHYHUZHZDQWWRFKDQJHRQVRPHRSHUDWLRQVR,/LVWDOORZXVWRGRWKDWHDVLO\ZLWKDWOHDVWFKDQJLQJLQWKHZKROHRIFRGHV

,QWHUIDFHVFDQQRWEHLQVWDQWLDWHVRLWVKRXOGEHLQVWDQWLDWHIURP/LVW

'LIIHUHQFHEHWZHHQ&RQFUHWH&ODVVDQG,QWHUIDFH

&RQFUHWH&ODVVLQKHULWVIURPMXVW21(FODVVEXWLW&DQLPSOHPHQWVRQHRU025(WKDQRQHLQWHUIDFHV



2QWKHRWKHUKDQGLQWHUIDFHNHHSV\RXUSURJUDPH[WHQVLEOHDQG'HFRXSOH7KHFODVVHVDUHLQGHSHQGHQWIURPHDFKRWKHUVRHUURUH[FHSWLRQDQGIDLOXUHZLOOKDSSHQUDUHO\LQIXWXUHFKDQJLQJFRGHE\LQWHUIDFHV

3RO\PRUSKLVP:KHQ\RXDUHXVLQJLQWHUIDFH\RXDEVROXWHO\REVHUYHDQGGRSRO\PRUSKLVPDQGRRS,WPHDQVHQFDSVXODWH\RXUGHVLJQHU,QWHUIDFHPHDQVDSRLQWRUDQRGHWRMRLQWZRSDUWWRHDFKRWKHULWPHDQVPDNLQJORZGHSHQGHQF\IURPWZRSDUWDQGPDNHDMRLQWVHFWLRQWRPDNHIOH[LEOHFKDQJHLQIXWXUH

,(QXPHUDEOH,(QXPHUDEOHLVVXLWDEOHMXVWIRULWHUDWHWKURXJKFROOHFWLRQDQG\RXFDQQRWPRGLI\$GGRU5HPRYHGDWD,(QXPHUDEOHEULQJ$//GDWDIURPVHUYHUWRFOLHQWWKHQILOWHUWKHPDVVXPHWKDW\RXKDYHDORWRIUHFRUGVVR,(QXPHUDEOHSXWVRYHUKHDGRQ\RXUPHPRU\



,4XHU\DEOH:KHQHYHUZHHQFRXQWHUWRKXJHGDWDZLWKVRPDQ\UHFRUGVVRZHKDYHWRUHGXFHRYHUKHDGIURPDSSOLFDWLRQ,4XHU\DEOHSUHSDUHVKLJKSHUIRUPDQFHLQVXFKVLWXDWLRQVKXJHGDWDE\ILOWHULQJGDWDILUVWO\DQGWKHQVHQGLQJILOWHUHGGDWDWRFOLHQW



)ROORZ(QWLW\)UDPHZRUN'DWDEDVH)LUVWIURPWKLVDUWLFOHIRUPDNLQJ'%&RQWH[W

'DWD$FFHVV



64/3URILOHU

+RZWRWUDFH\RXUTXHU\JHQHUDWHV764/+RZPDQ\UHFRUGVZLOOEHORDGHG

6WHS

6WDUW!0664/6HUYHU!3HUIRUPDQFH7RROV!64/6HUYHU3URILOHU



6WHS

64/6HUYHU3URILOHU!)LOH!1HZ7UDFH

6WHS

&RQQHFWZLWK\RXXVHUQDPHDQGSDVVZRUG

6WHS

*HQHUDO7DE!8VHWKH7HPSODWH6WDQGDUG



6WHS

(YHQW6HOHFWLRQ7DE!(YHQW764/!6HOHFW64/%DWFK&RPSOHWHG_6HOHFW6KRZDOO&ROXPQV

3UHVV&ROXPQ)LOWHU!'DWDEDVH1DPH/LNH'DWD$FFHVV

3UHVV5XQ



6WHS

*R7R0664/6HUYHU0DQDJHPHQW6WXGLR!&RXQWDOORIUHFRUGVUHFRUGV

6WHS

,(QXPHUDEOHJHQHUDWHV



,4XHU\DEOHJHQHUDWHV



,&ROOHFWLRQ,&ROOHFWLRQLQKHULWVIURP,(QXPHUDEOH7KHUHLVRQHGLIIHUHQFH

\RXFDQILQG,(QXPHUDEOH>L@!,QGH[%DVHG

\RXFDQ127ILQG,&ROOHFWLRQ>L@!1RW,QGH[%DVHG



6WDFN*HQHULF



3XVK

3RS

4XHXH*HQHULF(QTXHXH



'HTXHXH

'LFWLRQDU\DQG,'LFWLRQDU\'LFWLRQDU\LV*(1(5,&ZKLOH+DVK7DEOHLVQRWJHQHULF'LFWLRQDU\7.H\79DOXH!7KHUHLVDWLQ\GLIIHUHQFHEHWZHHQWKHPWKDWLIGLFWLRQDU\FDQQRWILQGVSHFLILFNH\ZLOOWKURZDQH[FHSWLRQZKLOH+DVK7DEOHMXVWUHWXUQVQXOO

,'LFWLRQDU\LVLQWHUIDFHDQGLI\RXHVWLPDWHELJFKDQJHVLQIXWXUHXVH,'LFWLRQDU\LQVWHDGRI'LFWLRQDU\

09&7XWRULDOKWWSWHFKQLFDOFRVPLFYHUVHLQIR$UWLFOH,QGH[

'DWD$FFHVV/D\HU7XWRULDOKWWSWHFKQLFDOFRVPLFYHUVHLQIR$UWLFOH,QGH[

5HIHUHQFHV

PVGQPLFURVRIWFRP&RPPRQO\8VHG&ROOHFWLRQ7\SHV

KWWSZZZFRGHSURMHFWFRP$UWLFOHV,(QXPHUDEOH9V,4XHU\DEOH

KWWSZZZGRWQHWWULFNVFRP7XWRULDOOLQT,6



KWWSZZZFODXGLREHUQDVFRQLFKZKHQWRXVHLHQXPHUDEOHLFROOHFWLRQLOLVWDQGOLVW

KWWSZZZGRWQHWSHUOVFRP

)HHGEDFN

)HHOIUHHWROHDYHDQ\IHHGEDFNRQWKLVDUWLFOHLWLVDSOHDVXUHWRVHH\RXUFRPPHQWVDQGYRWHDERXWWKLVFRGH,I\RXKDYHDQ\TXHVWLRQVSOHDVHGRQRWKHVLWDWHWRDVNPHKHUH

/LFHQVH7KLVDUWLFOHDORQJZLWKDQ\DVVRFLDWHGVRXUFHFRGHDQGILOHVLVOLFHQVHGXQGHU7KH&RGH3URMHFW2SHQ/LFHQVH&32/

6KDUH

$ERXWWKH$XWKRU

0DKVD+DVVDQNDVKL 6RIWZDUH'HYHORSHU*HUPDQ\

,KDYHEHHQZRUNLQJZLWK1HWIUDPHZRUNIRU\HDUV,CGOLNHWRFKDOOHQJHZLWKFRPSOH[SUREOHPWKHQPDNHLWHDV\IRUXVLQJHYHU\RQH7KLVLVWKHEHVWMR\

,&70DVWHU)RXQGHUDWWHFKQLFDOFRVPLFYHUVHLQIR)UHH:HE7XWRULDO'LDPRQGLVQRWKLQJH[FHSWWKHSLHFHVRIWKHFRDOZKLFKKDYHFRQWLQXHGWKHLUDFWLYLWLHVILQDOO\WKH\KDYHEHFRPH'LDPRQG

$UWLFOHRI7KH&RPPXQLW\6SRWOLJKWLQ0LFURVRIW$631(7:HGQHVGD\)HEUXDU\ZZZDVSQHW

$UWLFOHRI7KH'D\LQ0LFURVRIW$631(77XHVGD\)HEUXDU\



3HUPDOLQN_$GYHUWLVH_3ULYDF\_7HUPVRI8VH_0RELOH:HE__/DVW8SGDWHG)HE 6HOHFW/DQJXDJH

$UWLFOH&RS\ULJKWE\0DKVD+DVVDQNDVKL(YHU\WKLQJHOVH&RS\ULJKW&RGH3URMHFW

List vs IEnumerable vs IQueryable vs ICollection vs IDictionary - CodeProject

Documents