in reply to Ouch! Each! Reentrant it is not

Rewind it before using each: 
sub find_2{
    keys %hash;
    while (my ($key,$val) = each(%hash)) {
        return "The key for 2 is $key\n"  if $val == 2;
    }
    die "could not find 2";
}

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Re^2: Ouch! Each! Reentrant it is not
by Thilosophy (Curate) on Jul 15, 2005 at 09:38 UTC
    Rewind it before using each.

    I did that at first, but then I changed it to rewind after use.

    Because if you rewind it only before, and then leave the iterator "open", your own piece of code is fine, but it will greatly confuse the next person who happens to call keys, values or each. So I decided that cleaning up after myself is the better way here.

    Update As pointed out by ysth, it would only greatly confuse any other users of each, and not affect keys or values.

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      keys and values don't depend on the iterator, just each.
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        Experimentation proves you right. Interesting. I must have mis-interpreted the perldoc:

        There is a single iterator for each hash, shared by all "each", "keys", and "values" function calls in the program.

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