I have two arrays, let's call them @a1 and @a2. What I'm trying to do is obtain elements from @a2 using the values in @a1 as indices. My current attempt doesn't work properly.
foreach (@a1) {
print $a2[$_] . "at" . $_;
}
This only prints $_ but not $a2[$_].
I sense there is a trivial solution to this, but I just can't find it.
There is nothing wrong with the code you have. I have tested a small script and it works as expected. Asi i suggested in my comment, try using something like Data::Dumper to see whats in the arrays before the loop.
use strict;
use warnings;
use Data::Dumper;
my @a1 = (0..4);
my @a2 = ("a".."e");
print Dumper \@a1, \@a2;
foreach (@a1){
print $a2[$_]." at ".$_."\n";
}
OUTPUT
$VAR1 = [
0,
1,
2,
3,
4
];
$VAR2 = [
'a',
'b',
'c',
'd',
'e'
];
a at 0
b at 1
c at 2
d at 3
e at 4
there's no reason your code shouldn't work as long as the values of the first array are valid addresses in the second array. but if all you really want to do is just get the values and address of the second array, you could just do:
for my $i (0..$#a2) {
print "$i: $a2[$i]","\n";
}
$#a2 is the last element address of the array.
my @a1 = (4,6,8) as those might be key fields he is interested in. rather than every element in the array
perl -E '@a1=(0,1,2); @a2=qw(a b c); for (@a1) {say $a2[$_]}'givesa,bandc..Data::Dumperto check what in a1 and a2 just before the foreach loopfor ( @a2[@a1] ) { say }