Is the behavior defined when modifying $_ when doing a foreach directly on a %hash variable, i.e., without using keys or values, to iterate through the hash keys *and* values? If it's specified somewhere in the man pages it's not clear to me so pointing me to where would be fine.

In other words, is it defined that the example code below:

#!/usr/bin/env perl
use warnings;
use strict;

my @array;
my %hash;

%hash = (1, 2, 3, 4);
@array = %hash;

print("<<<< @array\n");

foreach (%hash) {
    print("<< $_\n");
    $_ *= 11;
    print(">> $_\n");
}

@array = %hash;

print(">>>> @array\n");

outputs the following (last line is key)?

<<<< 1 2 3 4
<< 1
>> 11
<< 2
>> 22
<< 3
>> 33
<< 4
>> 44
>>>> 1 22 3 44

(This is Perl v5.26.1.)

My project is to implement a version of chomp that tries to modify its arguments as close to what chomp is capable of though I realize you cannot specify a prototype on a subroutine that handles it exactly the same.

Basically I'm trying to determine if it is defined what happens when a %hash argument is passed to a sub (@) prototyped subroutine.


In reply to Modifying $_ in foreach (%hash) by dse

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