I'd like to get the substring s2 in this string pattern
('s1', 's2', 's3', 's4')
with s1, s2, s3 being any string (with variable length) and the commas, the blanks and the brackets are those specific chars. I wonder: is there a pythonic, simply way to do it using regex matching or similar?
A regular expression as follows could be used:
import re
print re.findall("'(\w+)'", "('s1', 's2', 's3', 's4')")
Giving you a list of all of the entries as follows:
['s1', 's2', 's3', 's4']
So for s2:
print re.findall("'(\w+)'", "('s1', 's2', 's3', 's4')")[1]
As another alternative, the Python csv module could be used which deals quite well with various quoting scenarios:
import csv, StringIO
text = "('s1', 's2', 's3', 's4')"
print next(csv.reader(StringIO.StringIO(text.strip("()")), skipinitialspace=True, quotechar="'"))[1]
This first converts the text into a file type object which is needed using the csv reader.
You may get the answer through ast
import ast
h = "('s1', 's2', 's3', 's4')"
print ast.literal_eval(h)[1]
or
Through splitting.
print h.split(', ')[1]
or
print h.split("', '")[1]
straightforward with strip and split alltogether.
s="""('s1', 's2', 's3', 's4')"""
print s.split()[1].strip("',")
but regex is more clean:
import re
s="""('s1', 's2', 's3', 's4')"""
print re.findall("\w\d",s)[1]
ast.literal_eval(s)[1]s1,s2, ...?