Say I wanted to do this:

    $str =~ s/foo/bar/g;

    $str =~ s/bar/foo/g;

I would obviously have a problem, because a "foo" in the original would be changed back to a "foo". by the second replacement.

The way I do it manually in a text/WP app is:

    $str =~ s/foo/%%%/g; # or any other extremely unlikely string

    $str =~ s/bar/foo/g;

    $str =~ s/%%%/bar/g;

but is there a better way to do it?

    $str =~ s/(foo|bar)/$1 eq 'foo'?'bar':'foo';/ge;

works, and benchmarks better than the other way (string with 1,000 chars). Anything else monks can suggest? 
percentage_way: 130 wallclock secs (126.01 usr +  0.29 sys = 126.30 CP
+U) @ 7917.66/s (n=1000000)
   rhs_way: 49 wallclock secs (46.50 usr +  0.13 sys = 46.63 CPU) @ 21
+445.42/s (n=1000000)

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In reply to Swap foo and bar in text? by Cody Fendant

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