Difference between revisions of "Python-Perl cheatsheet"

Revision as of 17:08, 25 April 2011

what	Python	Perl	notes
null type	None	undef	not exactly identical
String concatenation	"py"+"thon"	"pe"."rl"
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, item;	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.

@@ Line 24: / Line 24: @@
 |"pe"."rl"
 |
+|-
+|colspan=4|<span style="color:#009000">'''Arrays'''<span style="color:#009000">
 |-
 |declare a list