Which python re module to pick for translating a perl regular expression

Question

I have the perl regular expression /VA=\d+:(\S+):ENSG/ which is used in a if statement as

if ($info =~ /VA=\d+:(\S+):ENSG/){
    $gene =$1;

I am trying to figure out what the best way to replicate this in python would be. Right now I have

gene_re = re.compile(r'VA=\d+:(\S+):ENSG')
this_re = re.search(gene_re, info)
if this_re is not None:
    gene = info[this_re.start(0):this_re.end(0)]

Is this a good way to translate it? I guess this is one area where perl is actually more readable than python.

Note that the python regular expression is compiled because the next three lines are actually inside a loop.

Answer 1

You could use

gene = this_re.group(1)

instead of

gene = info[this_re.start(0):this_re.end(0)]

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By the way, the Python re module caches the N most recently used regex patterns, so (unless you have a very large number of patterns) it is not necessary to pre-compile it.

For Python 2.7, re._MAXCACHE (i.e. N) is 100.