How to combine regexps?

kj at
Wed Aug 5 22:36:07 CEST 2009

In <h5cotl$or0$1 at> kj < at> writes:

>One of the nice things one can do with Perl's regexp's is illustrated
>in the following example:

>my $gly = qr/gg[ucag]/i
>my $ala = qr/gc[ucag]/i;
>my $val = qr/gu[ucag]/i;
>my $leu = qr/uu[ag]|cu[ucag]/i;
>my $ile = qr/au[uca]/i;

>my $aliphatic = qr/$gly|$ala|$val|$leu|$ile/;

>In other words, one can build regular expressions by re-combining
>other regular expressions.

>Is there a way to do this with Python's regexps?

OK, answering my own question here, it looks like the only way to
do this is to leave the "component" expressions as regular strings,
and combine those, before compiling them into regexps.

Easy enough.


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