I was wondering if there were any Python packages out there that detects a regular expression from a string. Conceptually this is easy enough to do but I wanted to see if there was anyone else who has solved this problem.

To the extent that I looked around on my own, I've read the re package docs and didn't find it, and I read the best hits I could find on Stack Overflow and couldn't find one either. I've googled it and the hits I find are how to use regex to parse strings. I've searched through PyPI but the only hit I could find is 'regexgen 1.0' and that didn't seem to lead anywhere...

To be clear, what I am looking for is something to the effect of:

def detect_regex(some_string):[does stuff..]return regular_expression

Thoughts would be greatly appreciated. If there aren't any, I can write this myself. I just didn't want to waste time re-creating what's already been done. Thanks!

Edit: I may not have been very clear in my question; the regex 'foo' does match the string 'foo' but my goal is the following -- given the three strings with values foo123abc, abc078963bar, and xyz8940baz, the return would be ^[a-z]+[0-9]+[a-z]+$... hypothetically. So the regex would be "general" to some extent.

Very limited, but a bit of fun. Only deals with alpha and numerics as per your examples. Was also just curious and hopefully this helps to give you a suitable starting point:

def auto_re(text):cur = first = str.isalpha(text[0])count = 0for letter in text:if str.isalpha(letter) != cur:cur = not curcount += 1modes = ["[0-9]+", "[a-z]+"]return "^" + modes[first] + (count/2) * (modes[not first ] + modes[first]) + (count%2) * (modes[not first]) + "$"tests = ["foo123abc", "abc078963bar", "xyz8940baz", "1a", "a1", "1a2b3c", "a12b3c"]for test in tests:print "%-20s %s" % (test, auto_re(test))

Gives the following output:

foo123abc            ^[a-z]+[0-9]+[a-z]+$
abc078963bar         ^[a-z]+[0-9]+[a-z]+$
xyz8940baz           ^[a-z]+[0-9]+[a-z]+$
1a                   ^[0-9]+[a-z]+$
a1                   ^[a-z]+[0-9]+$
1a2b3c               ^[0-9]+[a-z]+[0-9]+[a-z]+[0-9]+[a-z]+$
a12b3c               ^[a-z]+[0-9]+[a-z]+[0-9]+[a-z]+$