Re: Looping backwards through two arrays at once?

[ikegami]

"Perl-style" for loop:

for my $i (reverse 0..$#a) {
   print("$a[$i], $b[$i]\n");
}

"C-style" for loop:

for (my $i=@a; $i--; ) {
   print("$a[$i], $b[$i]\n");
}

Update: Fixed crossed wires.

[Limbic~Region]

ikegami,
Your suggestion of a C style for loop as an alternative feels odd to me. I would have written it as a while loop as it feels more natural.

my $i = @array;
while ( $i-- ) {
    # ...
}

[ikegami]

I prefer for over while because

• the index is scoped to the loop, and
• I find it more readable since the bounds of the loop are on a single line.

[kutsu]

umm....don't you mean for my $i (reverse 0 .. $#a) on the first example?

Update: Already corrected it, it seems :).

[holli]

From the belly I would have said that

for my $i (reverse 0..$#a)

would cast the list into existance, but as it seems that isn't the case (Perl 5.8).

[ikegami]

Actually, it does cast the list into existance, even in 5.8. I mentioned this elsewhere in this thread. This thread has a discussion on this issue.