Let's say I have such a list:
['word_4_0_w_7', 'word_4_0_w_6', 'word_3_0_w_10', 'word_3_0_w_2'] and I want to sort them according to number that comes after "word" and according to number after "w". It will look like this:
['word_3_0_w_2', 'word_3_0_w_10', 'word_4_0_w_6', 'word_4_0_w_7'] What comes in mind is to create a bunch of list and according to index after "word" stuff them with sorted strings according "w", and then merge them.
Is in Python more clever way to do it?
Use Python's key functionality, in conjunction with other answers:
def mykey(value): ls = value.split("_") return int(ls[1]), int(ls[-1]) newlist = sorted(firstlist, key=mykey) ## or, if you want it in place: firstlist.sort(key=mykey) Python will be more efficient with key vs cmp.
You can provide a function to the sort() method of list objects:
l = ['word_4_0_w_7', 'word_4_0_w_6', 'word_3_0_w_10', 'word_3_0_w_2'] def my_key_func(x): xx = x.split("_") return (int(xx[1]), int(xx[-1])) l.sort(key=my_key_func) Output:
print l ['word_3_0_w_2', 'word_3_0_w_10', 'word_4_0_w_6', 'word_4_0_w_7'] edit: Changed code according to comment by @dwanderson ; more info on this can be found here.
key functionality, rather than the cmp, since sorting will calculate the key O(n) times but can do O(n**2) cmps (I think). Simple change would just be: def key(x): xx = x.split("_"); return int(xx[1]), int(xx[-1]) and then l.sort(key=mykey). The output will be the same, but it's more efficient, and the preferred Python way.You can use a function to extract the relevant parts of your string and then use those parts to sort:
a = ['word_4_0_w_7', 'word_4_0_w_6', 'word_3_0_w_10', 'word_3_0_w_2'] def sort_func(x): parts = x.split('_'); sort_key = parts[1]+parts[2]+"%02d"%int(parts[4]) return sort_key a_sorted = sorted(a,key=sort_func) The expression "%02d" %int(x.split('_')[4]) is used to add a leading zero in front of second number otherwise 10 will sort before 2. You may have to do the same with the number extracted by x.split('_')[2].
sorted(words, key=lambda word: (int(word[5]), int(word[11:]))