Re: Accessing array elements

If you look at code written by Perl experts then you'll probably notice that they very rarely use the C-style for loop like you're using here. Most people find the shell-style foreach loop far easier to deal with.

In this case, I think you want:

foreach my $i (0 .. ($#array/2) - 1) {
  ...
}
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Re^2: Accessing array elements by JavaFan (Canon) on Jun 18, 2009 at 15:02 UTC
But the set of people who avoid using C-style for loop are typically the ones that avoid $# as well. I do use the C style for loop if I want the index, because, IMO, it's easier to avoid off-by-one errors than using foreach style. The latter means you either have to use '- 1', or remember to use '$#'. `for (my $i = 0; $i < @array; $i++) {...}` [download] is standard idiom which translates easily between languages. Both `foreach my $i (0 .. @array - 1) {...}` [download] and `foreach my $i (0 .. $#array) {...}` [download] feel artificial, and Perl specific to me. And they both have their ugliness (either `-1` or `$#array`).	[reply] [d/l] [select]
Re^2: Accessing array elements by AnomalousMonk (Archbishop) on Jun 18, 2009 at 16:40 UTC
`foreach my $i (0 .. ($#array/2) - 1) { ... }` This produces an off-by-one error. Either `($#array/2)` or the uglier `(@array/2) - 1` works as I understand the OPer requires. `>perl -wMstrict -le "my @ra = qw(a A b B c C d D e E); for my $i (0 .. ($#ra/2) - 1) { print qq{$ra[ $i * 2 ] : $ra[ $i * 2 + 1 ]}; } " a : A b : B c : C d : D >perl -wMstrict -le "my @ra = qw(a A b B c C d D e E); for my $i (0 .. ($#ra/2)) { print qq{$ra[ $i * 2 ] : $ra[ $i * 2 + 1 ]}; } " a : A b : B c : C d : D e : E` [download]	[reply] [d/l] [select]