How to use a custom comparison function in Python 3?
In Python 2.x , I could pass custom function to sorted and .sort functions
>>> x=['kar','htar','har','ar']
>>>
>>> sorted(x)
['ar', 'har', 'htar', 'kar']
>>>
>>> sorted(x,cmp=customsort)
['kar', 'htar', 'har', 'ar']
Because, in My language, consonents are comes with this order
"k","kh",....,"ht",..."h",...,"a"
But In Python 3.x , looks like I could not pass cmp keyword
>>> sorted(x,cmp=customsort)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'cmp' is an invalid keyword argument for this function
Is there any alternatives or should I write my own sorted function too?
Note: I simplified by using "k", "kh", etc. Actual characters are Unicodes and even more complicated, sometimes there is vowels comes before and after consonents, I've done custom comparison function, So that part is ok. Only the problem is I could not pass my custom comparison function to sorted or .sort
使用key参数（并按照关于如何将旧的cmp函数转换为key函数的配方）。
使用key关键字和functools.cmp_to_key来转换您的比较函数：
sorted(x, key=functools.cmp_to_key(customsort))
Instead of a customsort(), you need a function that translates each word into something that Python already knows how to sort. For example, you could translate each word into a list of numbers where each number represents where each letter occurs in your alphabet. Something like this:
my_alphabet = ['a', 'b', 'c']
def custom_key(word):
numbers = []
for letter in word:
numbers.append(my_alphabet.index(letter))
return numbers
x=['cbaba', 'ababa', 'bbaa']
x.sort(key=custom_key)
Since your language includes multi-character letters, your custom_key function will obviously need to be more complicated. That should give you the general idea though.
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