Create sortCharactersByFrequency.py

Author: kanglicheng

Kangli/Hash Table/sortCharactersByFrequency.py

@@ -0,0 +1,10 @@
+from operator import itemgetter
+class Solution(object):
+ def frequencySort(self, s):
+ d, st = {}, ""
+ for c in s:
+ d[c] = 1 if c not in d else d[c] + 1
+ arr = sorted(d.items(), key=itemgetter(1), reverse = True) 
+ for pair in arr:
+ st += pair[0]*pair[1]
+ return st