(digression) preferred syntax for index of last array element?

For times when I access the last element of an array, I use @array[-1]; however, when I need to know the value of the last index, such as in a loop above, I have seen people recommend two approaches. Let's use the for snippet from the above -- it could be written in either of:

for my $y (0..@x-1) { }
# or #
for my $y (0..$#x) { }
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Is there a practical difference?

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Re: (digression) preferred syntax for index of last array element? by ikegami (Patriarch) on Sep 22, 2005 at 14:39 UTC
There might be an extra op in the `@x-1` version, but using the latter because of this would be "premature optimization". Pick whichever one you prefer. Personally, I prefer beating around the bush and use last (`$#x`) if I mean last, and count (`@x`) if I mean count. The down side is that the reader must be familiar with both ops. But that's assuming (deprecated) `$[` is left untouched.. If `$[` is 1, they're both wrong. The solution for `$[ = 1` is `for my $y (1..$#x) { }` or `for my $y (1..@x) { }` and the general solution is `for my $y ($[..$#x) { }` or `for my $y ($[..$[+@x-1) { }`	[reply] [d/l] [select]
Re^2: (digression) preferred syntax for index of last array element? by ambrus (Abbot) on Sep 23, 2005 at 16:24 UTC
If you don't want to mess with `$[`, install a recent version of perl, where `$[` has a lexical effect, like the `integer, locale, warning, strict` pragmas. (That could still cause problems if someone depends heavily on the old behaiviour of `$[`.)	[reply] [d/l] [select]