When you use a for(each) loop in this way it edits the elements of the array in-place: 
    #!/usr/bin/perl -wl

    use strict;


    my @a = (1,2,3);
    print "@a";


    foreach (@a) {
        $_ *= 2;
    }

    print "@a";


    foreach my $item (@a) {
        $item *= 2;
    }

    print "@a";

    __END__
    Prints:

    1 2 3
    2 4 6
    4 8 12

[download]

Here is the relevant detail from the "Foreach Loops" section of perlsyn:

If any element of LIST is an lvalue, you can modify it by modifying VAR inside the loop.

--
John.

In reply to Re: Why is my array getting changed? by jmcnamara
in thread Why is my array getting changed? by Limbic~Region

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