Python regex get with zero or more occurences within the pattern

Question

I've a working regex that's giving me the results that I want, yet it doesn't contain the safety it needs. (Fool-proof) Lets say I have a regex that matches parts of a path, something along the lines of: ``` import re path = "C:/Projects/foo/dev/model/props/furniture/couch/data/fbx" regex = re.compile("(.+)/dev/model/(.+)/(.+)/data/fbx") m = regex.search(path) if m: print m.groups() # ('C:/Projects/foo', 'props/furniture', 'couch') ``` I want to be able to replace the match any character up till the following part of the regex with something that will match one or more folders. Let's say we define a folder for simplicity as word characters (none or more) ending with a slash it would be: ``` [\w]*/ ``` And I want to group zero to ten of those, how would I do that? In my mind I had something like (note that this doesn't work!): ``` # match any number of word characters ending with a slash zero to ten times ([[\w]*/]{0,10}) # match any number of word characters ending with a slash zero t…

Accepted Answer

The `[]` in your regexp will not group the regexp. It is used to specify the character-class.

Maybe this will work-

```
\w*/{0,10}
```

And for grouping just use `()`

```
(\w*/){0,10}
```

EDIT

Based on your edited question, I think what you want is that 0-3 occurrences of the directory name match and then a file name matches too.

Assuming only alphabets in file names (and an optional upto three character extension)

```
^((?:[:\w]+/){0,3})(\w+(?:\.\w{1,3})?)?$
```

This is very big but can be broken into two parts

This is what you already have

```
((?:[:\w]+/){0,3})
```

And what I add

```
(\w+(?:\.\w{1,3})?)?
```

This is an optional filename at the end. (If it is not optional you can remove the last `?`). The filename itself can either be made up of only alphabtes or also have an extension of maximum 3 characters

Adding `^` and `$` will stop spurous matches

```
>>> pat=re.compile('^((?:[:\w]+/){0,3})(\w+(?:\.\w{1,3})?)?$')
>>> my_str='fwefw/wfwf/wefwf/dde.cdf'
>>> pat.search(my_str).groups()
('fwefw/wfwf/wefwf/', 'dde.cdf')
>>> my_str='fwefw/dde.cdf'
>>> pat.search(my_str).groups()
('fwefw/', 'dde.cdf')
```

Python regex get with zero or more occurences within the pattern

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