Question

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How do I perform a Perl substitution on a string while keeping the original?
Perl: Use s/ (replace) and return new string

please, fell free to modify the title of this question if you find a better way to describe it.

Imagine we have:

   my $foo = something;
   my $newfoo = $foo =~ s/.*/something else/;

I thought I will have $newfoo = something else, while I found it equal to 1. I imagine that this 1 is there to say ‘matching and replacing succeed’.

The only solution I’ve found is the sequent:

  my $foo = something;
  my $newfoo = $foo;
  $newfoo =~ s/.*/something else/;

Is there a way to accomplish the same task, i.e. creating a new variable with the result of the regexp without modifying the first variable, without the middle step?

Answer 1

You can assign and perform the substitution in any version of Perl with judicious use of parentheses:

(my $newfoo = $foo) =~ s/.*/something else/;

Using Perl v5.14 saves you one keystroke in this case (although there may be other benefits to v5.14)