#!/usr/bin/perl
my @my_arr = ("test1", "test2", "test3", "test2", "test5", "test2", "test6");
my $what = 'test2';
my $then = 'best2';
for ( my $i = 0; $i < @my_arr; $i++ ) {
my $value = $my_arr[ $i ];
$index{ $value } = $i if not exists $index{ $value }; }
if ( exists $index{ $what } ) { $my_arr[ $index{ $what } ] = $then;
}
print $_, "\n" for @my_arr;
IyEvdXNyL2Jpbi9wZXJsCgpteSBAbXlfYXJyID0gKCJ0ZXN0MSIsICJ0ZXN0MiIsICJ0ZXN0MyIsICJ0ZXN0MiIsICJ0ZXN0NSIsICJ0ZXN0MiIsICJ0ZXN0NiIpOwpteSAkd2hhdCA9ICd0ZXN0Mic7Cm15ICR0aGVuID0gJ2Jlc3QyJzsKCm15ICVpbmRleDsKZm9yICggbXkgJGkgPSAwOyAkaSA8IEBteV9hcnI7ICRpKysgKSB7CglteSAkdmFsdWUgPSAkbXlfYXJyWyAkaSBdOwoJJGluZGV4eyAkdmFsdWUgfSA9ICRpIGlmIG5vdCBleGlzdHMgJGluZGV4eyAkdmFsdWUgfTsKfQoKaWYgKCBleGlzdHMgJGluZGV4eyAkd2hhdCB9ICkgewoJJG15X2FyclsgJGluZGV4eyAkd2hhdCB9IF0gPSAkdGhlbjsKfQoKcHJpbnQgJF8sICJcbiIgZm9yIEBteV9hcnI7Cg==