None of my books have anything about using the substitution regexp with two sets of braces.

Using braces isn't what made the solution possible. Using braces is just a stylistic choice. Using the "e" modifier after the replacement is what made the solution possible. 

s/this/that/

[download]
is equivalent to any of these: 
s{this}{that}
s(this)(that)
s#this#that#

[download]

For more on the "e" modifier, see perlre.

If you want to learn what is possible in Perl, start reading the perldoc. Honestly it sounds silly, but take any kind of reference works to the toilet with you (like perldoc printouts), and read them whenever you are NOT trying to solve a problem. You'll gain familiarity with many features, and you'll be able to go back for more details when you need them at your desk.

--
[ e d @ h a l l e y . c c ]

In reply to Re^3: Matching multiple digits by halley
in thread Matching multiple digits by skoney

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