sub getArrayIndex {
     my $value = shift;
     for my $index(0..$#_) {
        return $index if $value eq $_[$index];
     }
     return -1;
}

##</code><code>##

for ($i=0,$i<$x,$i++)

##</code><code>##

# to just iterate over an array; each element assigned to $_
# changing $_ changes the original array element

for (@array) {
    # assigning to $_ here will change original array
    # comparing to $_ of course will not
}

# to iterate over a range
for (0..10) {
    # $_ will be set to 0 to 10 in sequence
}

# to iterate over a range with a named op
for $i(0..10) {
    # $i will be set to 0 to 10 in sequence
}

##</code><code>##

for (0..$#array) { }
for (0..@array) { }

##</code><code>##

@array = qw(1);
print "My array @array\n";
for (0..10) { 
    for (0..@array) {$array[$_]++}
}
print "My array @array\n";

##</code><code>##

My array 1
My array 12 11 10 9 8 7 6 5 4 3 2 1

##</code><code>##

# really short idiomatic version


sub getArrayIndex {
    map{return --$_ if $_[0] eq $_[$_]}(1..@_-1) and -1
}



# test code
@array = qw(0 2 4 6 8 10 12);
print getArrayIndex(6,@array),"\n";
print getArrayIndex(5,@array),"\n";