# shawnhcorey's code:
my @a = ( 1, 2, 3, 4, 2, 5, 7 );
my $last = $#a;
my $i = 0;
while( $i <= $last ){

  if( $a[$i] == 2 ){
    $last --;
    last if $i > $last;
  }

}continue{
  $i ++;
}
$#a = $last;
say "shawnhcorey: @a"; 

# OP's code
@a = ( 1, 2, 3, 4, 2, 5, 7 );
for (@a) {
    if ($_ == 2) {
        pop @a;
        last
    }
}
say "  OP vsespb: @a";