I was doing a relatively simple piece of code, 
for my $var (@vars) {
    print "Value: " . $hash_ref->{lc $var} . "\n" if exists $hash_ref-
+>{lc $var};
}

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I had to lc() the $var variable to for the key comparision. I started thinking, is there another way to do this? Well I could have done this, 
for my $var (@vars) {
    my $new_var = lc $var;
    print "Value: " . $hash_ref->{$new_var} . "\n" if exists $hash_ref
+->{$new_var};
}

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Then I started thinking, what if I wanted to do this except it was invalid Perl. 
for my $var = lc $_ (@vars) {
    print "Value: " . $hash_ref->{$var} . "\n" if exists $hash_ref->{$
+var};
}

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NOW, I am thinking, how does a value get from @vars to my $var? If there is an internal iterator used by the for loop, does it put a value into the variable assignment or can you put an expression in there in some way? I admit I have never seen it before, but it is Perl!

In reply to How a for() assignment works by Herkum

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