list returned from function

hotshot has asked for the wisdom of the Perl Monks concerning the following question:

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Re: list returned from function by japhy (Canon) on Jan 17, 2002 at 21:12 UTC
You need an extra layer of parens. `$elem = (myFunc())[5];` _____________________________________________________ Jeff`[japhy]`Pinyan: Perl, regex, and perl hacker. `s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;`	[reply] [d/l]
Re: Re: list returned from function by count0 (Friar) on Jan 17, 2002 at 21:28 UTC
In addition to japhy's excellent answer, I'd like to just point out what this is doing for anyone who might not quite understand why this works as it does. `(my_func())` forces the output of this function into list context as well as groups it for the `[5]` we're about to append. Now that `[5]` takes a slice of the list. Here's a simple example `sub foo { return qw(a b c d) } ( foo() )[1,3]; # Is the same as: ('a', 'b', 'c', 'd')[1,3]; # And effectively the same as @a = foo(); @a[1,3];` [download] You can read more about slicing in the book Effective Perl Programming (a must read =)	[reply] [d/l] [select]
Re: list returned from function by George_Sherston (Vicar) on Jan 18, 2002 at 02:43 UTC
The preceding answers assume that `MyFunc()` returns an array. If it returns an array reference, as it might, you need `sub MyFunc { my @ary = qw(a b c d e f g h i j); return \@ary; } my $foo = ${MyFunc()}[4];` [download] § George Sherston	[reply] [d/l] [select]
Re: Re: list returned from function by PrakashK (Pilgrim) on Jan 18, 2002 at 03:34 UTC
Nothing wrong with the above. But I prefer: `my $foo = (MyFunc())->[4];` [download] /prakash	[reply] [d/l]
Re: list returned from function by theorbtwo (Prior) on Jan 18, 2002 at 07:04 UTC
Above and beyond the exelent answers above, I'd just like to note that in newer perls, that works exactly as you wrote it -- it's special-cased in the source. I think the change is as of 5.6, but I can't seem to find it in the perldelta* manpages. Thanks, James Mastros, Just Another Perl Scribe	[reply]
Re: list returned from function by vagnerr (Prior) on Jan 18, 2002 at 01:35 UTC
You're nearly there... `$elem = (myFunc())[5];` [download] will do it	[reply] [d/l]
Re: list returned from function by thunders (Priest) on Jan 18, 2002 at 20:37 UTC
As some of the examples above illustrate, always remember that an array index starts at zero. When you asked for the "5 element" do you mean the "5th element"? `$elem = (myFunc())[4]; #fifth element $elem = (myFunc())[5]; #sixth element` [download] It may have just been a typo, but I thought I'd point it out	[reply] [d/l]
Re: list returned from function by Steve_p (Priest) on Jan 19, 2002 at 02:25 UTC
I would try: `$elem = (myFunc())[5];` [download] This is what works for me when I need a single field from localtime. For example, `$day = (localtime)[6];` [download]	[reply] [d/l] [select]