How to sort the line with the number inside?

Question

Possible duplicate:
Does Python have a built-in function for naturally sorting strings?

I have a list of strings containing numbers, and I cannot find a good way to sort them.
For example, I get something like this:

something1 something12 something17 something2 something25 something29 

using the sort() method.

I know that I probably need to somehow extract the numbers and then sort the list, but I have no idea how to do this in the easiest way.

Answer 1

You might be looking for sorting people (also known as natural sorting ):

 import re def atoi(text): return int(text) if text.isdigit() else text def natural_keys(text): ''' alist.sort(key=natural_keys) sorts in human order http://nedbatchelder.com/blog/200712/human_sorting.html (See Toothy implementation in the comments) ''' return [ atoi(c) for c in re.split(r'(\d+)', text) ] alist=[ "something1", "something12", "something17", "something2", "something25", "something29"] alist.sort(key=natural_keys) print(alist) 

profitability

 ['something1', 'something2', 'something12', 'something17', 'something25', 'something29'] 

PS. I modified my answer to use the Toothy natural sort implementation (posted in the comments here ), as it is significantly faster than my original answer.

---

If you want to sort the text using floating-point numbers, then you need to change the regular expression to match (for example, (\d+) ) to a floating-point regular expression :

 import re def atof(text): try: retval = float(text) except ValueError: retval = text return retval def natural_keys(text): ''' alist.sort(key=natural_keys) sorts in human order http://nedbatchelder.com/blog/200712/human_sorting.html (See Toothy implementation in the comments) float regex comes from /questions/23485/regular-expression-for-floating-point-numbers/173679#173679 ''' return [ atof(c) for c in re.split(r'[+-]?([0-9]+(?:[.][0-9]*)?|[.][0-9]+)', text) ] alist=[ "something1", "something2", "something1.0", "something1.25", "something1.105"] alist.sort(key=natural_keys) print(alist) 

profitability

 ['something1', 'something1.0', 'something1.105', 'something1.25', 'something2']