Perl replace multiple strings simultaneously

Question

Is there any way to replace multiple strings in a string? For example, I have the string hello world what a lovely day and I want to replace what a

Answer 1

Well, mainly it's not working as tr///d has nothing to do with your request (tr/abc/12/d replaces a with 1, b with 2, and removes c). Also, by default arrays don't interpolate into regular expressions in a way that's useful for your task. Also, without something like a hash lookup or a subroutine call or other logic, you can't make decisions in the right-hand side of a s/// operation.

To answer the question in the title, you can perform multiple replaces simultaneously--er, in convenient succession--in this manner:

#! /usr/bin/env perl
use common::sense;

my $sentence = "hello world what a lovely day";

for ($sentence) {
  s/what/it's/;
  s/lovely/bad/
}

say $sentence;

To do something more like what you attempt here:

#! /usr/bin/env perl
use common::sense;

my $sentence = "hello world what a lovely day";

my %replace = (
  what => "it's",
  lovely => 'bad'
);

$sentence =~ s/(@{[join '|', map { quotemeta($_) } keys %replace]})/$replace{$1}/g;

say $sentence;

If you'll be doing a lot of such replacements, 'compile' the regex first:

my $matchkey = qr/@{[join '|', map { quotemeta($_) } keys %replace]}/;

...

$sentence =~ s/($matchkey)/$replace{$1}/g;

EDIT:

And to expand on my remark about array interpolation, you can change $":

local $" = '|';
$sentence =~ s/(@{[keys %replace]})/$replace{$1}/g;
# --> $sentence =~ s/(what|lovely)/$replace{$1}/g;

Which doesn't improve things here, really, although it may if you already had the keys in an array:

local $" = '|';
$sentence =~ s/(@keys)/$replace{$1}/g;