in reply to Re: Initialization of arrays
in thread Initialization of arrays

You can rewrite it like this:
for my $y (0..@x)

You mean:
for my $y (0..$#x)

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(digression) preferred syntax for index of last array element?
by radiantmatrix (Parson) on Sep 22, 2005 at 14:28 UTC

    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?

    <-radiant.matrix->
    Larry Wall is Yoda: there is no try{} (ok, except in Perl6; way to ruin a joke, Larry! ;P)
    The Code that can be seen is not the true Code
    "In any sufficiently large group of people, most are idiots" - Kaa's Law
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      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) { }

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        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 $[.)

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