05 0 1–2 2 UN Transaction Code

##</code><code>##

$string = "05 0 1–2 2 UN Transaction Code";

$found = 0;     # Make a fist with left hand (no fingers)

$position = 0;  # We're at the start of the string; 
                # put your right index finger there.


while( $found != 5 && $position != length $string ) {    # Set up a loop that stops once
                                                         # we've extended all five fingers.

  # Check if the character at the current position is a space.
  if( substr( $string,$position,1) eq q{ } ) {

    # If it is, replace it with a comma.
    substr( $string, $position, 1, q{,} );

    ++$found;  # And extend one finger to count that we
               # found a space.

  }

  ++$position;  # Each time through the loop, advance our
                # position marker to the next character.

}  # Repeat unless we're done.