use strict;
use warnings;

my $arrayref = ['A','_B','C'];

for my $str (@$arrayref)
{
    print "BEFORE: str = $str\n";
}

for (@$arrayref)
{
    my $str = $_;
       $str =~ s/^_//;
    print "INNER:  str = $str\n";
}

for my $str (@$arrayref)
{
    print "AFTER:  str = $str\n";
}