use Perl

• Why is $array[0] such a bad thing? (Score:1)

  by Purdy (2383)

  As I understand it, the funny character demarks the context of the variable. I haven't played around with this (yet), but what if the array was a list of refs to other arrays? Would that be @array[0] or @$array[0]? If the former, then all the more reason the funny character helps, as it denotes the context.

  Jason
  • Re:Why is $array[0] such a bad thing? (Score:1)

    by Matts (1087) on 2001.11.15 4:47 (#1888) Journal

    Unfortunately it's worse than you think.
    
    @$array[0] binds the @ more tightly than the [0], so it expects $array to be an array ref, which you're de-referencing, rather than $array[0] being the array ref. Except it doesn't work, because as you know, you don't say @x[0], you say $x[0], so when you say @$array[0], it thinks you're dereferencing $array, not @array, and $array doesn't exist (well it might, but it's not what you meant).
    
    Now @{$x[0]} will give you the de-referenced array in the first entry in the @x array. Because here we're being explicit about the precedence using curlies to bind it. But it can get a bit more confusing, because say you wanted the second entry in the first array? i.e. given:
    
        my @x = ([1,2], [3,4]);
    
    So you want the "2" above. Now that's:
    
        my $two = @{$x[0]}[1];
    
    But we got a scalar! Now what happened to that "symbol means context" thing here? Screwey, huh?
    
    Fixing this is a Good Thing (tm).

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