RegEx-查找字符串中最后找到的符号的位置

Question

i am struggling with regex in Python, i would like to find the position of the last token in a String.

Example: "mydrive/projects/test/version01"

Now i would like to get the position of the symbol between "test" and "version01"

import re
txt = "mydrive/projects/test/version01"
p = re.compile("/^.*/(.*)$/")
m = re.search(p, txt)
m.group(0) 
#but m.group(0) delivers None

but with this i am getting "None" i tried several things, but couldn't get it find the pattern. By the way i got this regex from a javascript page, but i think the patterns are the same.

thank you very much!

Answer 1

You're using the re module in the wrong way.

You have 2 errors:

1. You try to use a compiled regexp object as if it were a pattern Actually this is perfectly fine, see search.sub 's documentation .
2. Python's re doesn't need the slashes around the regexp.

Either use:

p = re.compile("^.*/(.*)$")
m = p.search(txt)
m.group(0) 

Or:

m = re.search("^.*/(.*)$", txt)
m.group(0) 

Answer 2

You say: Now i would like to get the position of the symbol between "test" and "version01".

I don't see how the regex is going to help you much. You could try the following:

Reverse scan for the symbol, if you know what the symbol is (I am assuming you do, since it is in the regex too):

>>> txt = "mydrive/projects/test/version01"
>>> txt.rfind('/')
21

If you don't know the separator:

>>> import os.path
>>> len(os.path.dirname(txt))
21

Answer 3

I'm curious whether you're wanting to use re or are actually trying to split that filepath ?

os.path has all you need if that's the case, if not forgive me for answering a non asked question.

In [212]: import os
In [213]: os.path.split("mydrive/projects/test/version01")
Out[213]: ('mydrive/projects/test', 'version01')

Answer 4

If you're trying to find the position of the symbol bewteen "test" and "version01" I'd just use rfind :

txt = "mydrive/projects/test/version01"
print txt.rfind("/");

which prints out 21 .