Python regex over multiple newlines

Question

I have a string which contains multiple file paths, some of which contain arbitrary newlines within the path, and I want to parse the string using python so that only the filenames and extensions remain.

For example:

a/b/c/d/file1.c  
a/b/c/d/e/f/g/h/1/2/3/4/5/foo.c  
dir1/dir2/newlinedir  
/nextlinedir/bar.c

should be parsed to give output:

file1.c
foo.c
bar.c

I am using the following regular expression (the groups for the filename and extension must be separate for later purposes):

path_regex = re.compile(r'.*\/([^\/\.]*)(\.c){0,1}$', re.MULTILINE)
path_regex.sub(r'\g<1>\g<2>', input_string)

This will work on strings with single line paths but not paths that contain newlines. What should I do?

See this : <<< http://stackoverflow.com/questions/8384737/python-extract-file-name-from-path-no-matter-what-the-os-path-format >>> — thecreator232, Jun 30 '15 at 05:42
Unfortunately, that will not work for a path with a newline within it. — foobar1, Jun 30 '15 at 05:53

score 1 · Answer 1 · answered Jun 30 '15 at 05:42

1

Try this regex: (?:.*\/)(.+)\.(.+)

Use \1 to access filename and \2 to access extension

DEMO

answered Jun 30 '15 at 05:42

Anshul Rai

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Thank you for the answer, but I need to have dir1/dir2/newlinedir removed too, and move bar.c to the previous line. Only the filename and extension must remain, nothing else. – foobar1 Jun 30 '15 at 05:52

Avinash Raj · Answer 2 · 2015-06-30T05:58:22.443

1

You may try this,

>>> s = '''a/b/c/d/file1.c  
a/b/c/d/e/f/g/h/1/2/3/4/5/foo.c  
dir1/dir2/newlinedir  
/nextlinedir/bar.c'''
>>> print(re.sub(r'(?s).*?([^/]+\.c)', r'\1\n', s))
file1.c
foo.c
bar.c

or

>>> print(re.sub(r'(?s).*?([^/]+)(\.[^.\n]+)(?=$|\n)', r'\1\2\n', s))
file1.c  
foo.c  
bar.c

edited Jun 30 '15 at 05:58

answered Jun 30 '15 at 05:50

Avinash Raj

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OP said, *the groups for the filename and extension must be separate for later purposes* – Anshul Rai Jun 30 '15 at 05:51

score 1 · Accepted Answer · answered Jun 30 '15 at 06:12

1

^([\s\S]*?\/)(\w+\.c)

Try this.See demo.This will work multiline too.Use m or multiline flag.

https://regex101.com/r/rX1tE6/7

answered Jun 30 '15 at 06:12

vks

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score 0 · Answer 4 · answered Jun 30 '15 at 07:16

0

This simple regex also works and you can access the filename with extension using \1

([^/]*\.\w+)

answered Jun 30 '15 at 07:16

Martin Brandl

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score 0 · Answer 5 · answered Jun 30 '15 at 11:29

This is technically not what you are asking for, but maybe regex here is not the right tool, since now you have two problems.

I think this is what you are searching for:

pydoc os.path.basename

So try with this:

map(os.path.basename, text.split('\n'))

Python regex over multiple newlines

5 Answers5

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