Re: How do I replace a substring (if exists) with a different substring in a string?

[dkubb]

You can use substr, length, and index inside a while loop to do what you want:

  my $string  = '01234567890';
  my $find    = '0';
  my $replace = 'a';  

  my $pos = index($string, $find);

  while($pos > -1) {
    substr($string, $pos, length($find), $replace);
    $pos = index($string, $find, $pos + length($replace));
  }

IMHO you can't beat the following for readability:

  $string =~ s/\Q$find\E/$replace/g;

[dkubb]

Note: I found a bug in my earlier answer, since I can't edit it, I am posting this follow up. If the string to replace has the substring you are trying to find, it can get into an endless loop. Here is an updated ansewer:

  my $string  = '01234567890';
  my $find    = '0';
  my $replace = 'a';  

  my $pos = index($string, $find);

  while($pos > -1) {
    substr($string, $pos, length($find), $replace);
    $pos = index($string, $find, $pos + length($replace));
  }

In this case, an s/// regex is actually 5% faster.

[kocetoo]

actually you can change:

 substr( $string, $pos, $length( $find ), $replace );

with this one:

substr( $created, $pos, length( $find ), $replace );

$length is not function!!!