Difference between revisions of "Python-Perl cheatsheet"
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| sub function { ... } | | sub function { ... } | ||
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| + | |- | ||
| + | | | ||
| + | | return x | ||
| + | | ''[last evaluated expression is return value]'' | ||
| + | | Perl has no explicit return statement | ||
|- | |- | ||
|} | |} | ||
[[Category:Programming]] | [[Category:Programming]] | ||
Revision as of 12:16, 26 April 2011
See also the Perl Phrasebook on wiki.python.org
| what | Python | Perl | notes |
|---|---|---|---|
| null type | None | undef | not exactly identical |
| String concatenation | "py"+"thon" | "pe"."rl" | |
| if x == y | if ( $x == $y ) or if ( $x eq $y) | Perl requires parenthesis in a comparison (same for while). Perl uses different comparators for numbers and strings | |
| Arrays | |||
| declare a list | [1,2,3] | (1,2,3) | note that arrays contain only scalars! (1,2, (3,4), 5) becomes (1,2,3,4,5) |
| array length | len(array) | $#array + 1 | Python returns the length of array. Perl gives me the index of the last element. Also, the array value in a scalar context is (usually) its size. |
| range(1,100) | (1..100) | ||
| create a list from whitespaced values | "fred barney wilma dino".split() | qw( fred barney wilma dino); | You can use separators others than parenthesis, e.g. qw ! fred barney wilma dino ! |
| multiple assignment | fred, barney, dino = "flintstone", "rubble", None | ($fred, $barney, $dino) = ("flintstone", "rubble", undef); | |
| array concatenation | a+b | (@a, @b) | you can also mix like (@a, 3, @b, undef) |
| array.append(item) | push @array, item; | See also Perl's unshift() for attaching to the front of array | |
| val = array.pop() | val = pop @array; | See also Perl's shift() for removing from the front of array | |
| List iteration | for item in array | foreach $item (@array) | Note that $item is the real element of @array, so if you modify $item, you modify the array content |
| list.reverse() | @list = reverse @list; | Python is in place, Perl is not. Same for sort. | |
| Functions and subroutines | |||
| Subroutine/function declaration | def function(): ... | sub function { ... } | |
| return x | [last evaluated expression is return value] | Perl has no explicit return statement | |