python正则表达式模式re.search

Question

hello i am confused with python regular expression,here is my code:

import os,re,sys

t="LOC_Os01g01010.1 GO:0030234  F   enzyme regulator activity   IEA     TAIR:AT3G59570"
k =['LOC_Os01g01010']

re_search=re.search(re.escape(k[0] + r'.1   GO:\d{7}'),t,re.M|re.I|re.S)
if re_search is None:
      pass
else:
      print re_search.group()

"t" is my data and "k" is my goal.

What i want is "LOC_Os01g01010.1 GO:0030234" or "GO:0030234",but i don't know how to write the pattern.

Answer 1

Given your example and the expectation that in LOC_********.* the stars can be anything in the set [a-zA-Z0-9] I would suggest:

import os,re,sys

t="LOC_Os01g01010.1 GO:0030234  F   enzyme regulator activity   IEA      TAIR:AT3G59570"
k =['LOC_Os01g01010']

re_search=re.search("(LOC_[0-9A-Z]*)",t,re.M|re.I|re.S)
if re_search is None:
      pass
else:
      print re_search.group()

python regexthing.py yields LOC_Os01g01010 when I run it with python2.7. The (LOC_[0-9A-Za-z]*) is a capture group that captures the content of anything matching the expression LOC_[0-9A-Z]* . This expression will match LOC_ , LOC_ABCabc123 , LOC_a1B2C , etc.

I hope this answers your question.

Answer 2

I believe the following would solve your problem:

import re
t="LOC_Os01g01010.1 GO:0030234  F   enzyme regulator activity   IEA     TAIR:AT3G59570"
my_regex = re.compile(r'^LOC_(.)*GO:\d{7}',re.M|re.I|re.S)
searches = my_regex.search(t)
if searches:
    print searches.group()

Answer 3

If there's any solution at all, there is (provably) infinite solutions to a regex that can match a finite set of examples in an unbounded string.

That's a subsuming way to say that you need to be more specific since giving us only one example of what you're trying to match, we'll be able to produce multiple solutions for you, depending on what further (unspecified) assumptions we add ourselves.

Here are a few, with stated assumptions:

>>> import re
>>> t = "LOC_Os01g01010.1 GO:0030234  F   enzyme regulator activity   IEA     TAIR:AT3G59570"
>>> re.findall('\w+\.\d+', t) # any alphnumeric sequence, followed by dot and digits
['LOC_Os01g01010.1']
>>> re.findall('[A-Z]+_\w+\.\d+', t) # forcing token to start with capitals and underscore
['LOC_Os01g01010.1']
>>> re.findall('[A-Z]+_O[a-z01]+\.\d+', t) # forcing "O", and middle part to be only small letters and 0s and 1s
['LOC_Os01g01010.1']
>>> re.findall('^[A-Z]+_O[a-z01]+\.\d+', t) # forcing the pattern to be at the beginning of the string
['LOC_Os01g01010.1']```