How to use re.search as an integer ? Python

Question

So I have a string

s = '>n269412 | AK142815 | msdfhakjfdkjfs'

and I want to include everything up to but not including the first instance of '|'

so what I did was

import re

p = re.search('|',s)

print s[:p]

but i got this error

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: slice indices must be integers or None or have an __index__ method

I understand why it isn't working . . because that value is not an integer but is there any way I can use that value where the search found that element ?

`re.search` returns a match object or None, not an integer. – Ashwini Chaudhary Mar 12 '13 at 20:34 — Ashwini Chaudhary, Mar 12 '13 at 20:34
``p = s.find('|')`` or ``p = s.index('|')`` will fit better – eyquem Mar 12 '13 at 20:36 — eyquem, Mar 12 '13 at 20:36

score 5 · Accepted Answer · answered Mar 12 '13 at 20:36

5

Why even bother with a regex for this use-case?

s = '>n269412 | AK142815 | msdfhakjfdkjfs'
print s.partition('|')[0]

answered Mar 12 '13 at 20:36

Jon Clements

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score 3 · Answer 2 · answered Mar 12 '13 at 20:36

3

You do not need regular expressions for this:

first, rest = s.split('|', 1)

answered Mar 12 '13 at 20:36

Francis Avila

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Just to note - where the delimiter is not present - this will raise a `ValueError` – Jon Clements Mar 12 '13 at 20:39

score 2 · Answer 3 · answered Mar 12 '13 at 20:35

I think re.match() gives a more direct solution (i.e. match everything up to and not including the first |):

In [7]: re.match('[^|]*', s).group(0)
Out[7]: '>n269412 '

If there's no |, the entire string is returned. It is not entirely clear from the question whether this is what you want.

But as others have said, you don't really need a regex for this...

score 0 · Answer 4 · answered Mar 12 '13 at 20:37

re.search returns a match object containing more that just a single index.

What you probably want is the start index:

>>> s[:p.start()]
'>n269412 '

Btw. you need to fix your regular expression as this would just match either '' or '' (i.e. nothing). You want to use '\|':

p = re.search('\|', s)

score 0 · Answer 5 · edited May 23 '17 at 11:50

That error is because re.search returns a MatchObject, which you attempt to slice and cannot do. See the re.search documentation.

I would do the following:

s = '>n269412 | AK142815 | msdfhakjfdkjfs'

# look for the pipe character
findPipe = s.find("|")

# replace everything after the pipe with empty string
s = s.replace(s[findPipe:], "")

print s

See these two links for more info about slicing strings.

How to use re.search as an integer ? Python

5 Answers5