49. Group Anagrams

class Solution(object):
    def groupAnagrams(self, strs):
        """
        :type strs: List[str]
        :rtype: List[List[str]]
        """
        anagram_dict,result=collections.defaultdict(list),[]
        for string in strs:
            sorted_str=''.join(sorted(string))
            anagram_dict[sorted_str].append(string)
        for anagram in anagram_dict.values():
            result.append(anagram)
        return result