Python字典按值排序、包含字典的列表按字典值排序的方法

# -*- encoding=utf-8 -*-import operator# 按字典值排序（默认为升序）x = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}sorted_x = sorted(x.iteritems(), key=operator.itemgetter(1))print(sorted_x)# [(0, 0), (2, 1), (1, 2), (4, 3), (3, 4)]# 如果要降序排序,可以指定reverse=Truesorted_x = sorted(x.iteritems(), key=operator.itemgetter(1), reverse=True)print(sorted_x)# [(3, 4), (4, 3), (1, 2), (2, 1), (0, 0)]# 或者直接使用list的reverse方法将sorted_x顺序反转# sorted_x.reverse()# 取代方法是,用lambda表达式sorted_x = sorted(x.iteritems(), key=lambda x: x[1])print(sorted_x)# [(0, 0), (2, 1), (1, 2), (4, 3), (3, 4)]sorted_x = sorted(x.iteritems(), key=lambda x: x[1], reverse=True)print(sorted_x)# [(3, 4), (4, 3), (1, 2), (2, 1), (0, 0)]# 包含字典dict的列表list的排序方法与dict的排序类似,如下：x = [{'name': 'Homer', 'age': 39}, {'name': 'Bart', 'age': 10}]sorted_x = sorted(x, key=operator.itemgetter('name'))print(sorted_x)# [{'age': 10, 'name': 'Bart'}, {'age': 39, 'name': 'Homer'}]sorted_x = sorted(x, key=operator.itemgetter('name'), reverse=True)print(sorted_x)# [{'age': 39, 'name': 'Homer'}, {'age': 10, 'name': 'Bart'}]sorted_x = sorted(x, key=lambda x: x['name'])print(sorted_x)# [{'age': 10, 'name': 'Bart'}, {'age': 39, 'name': 'Homer'}]sorted_x = sorted(x, key=lambda x: x['name'], reverse=True)print(sorted_x)# [{'age': 39, 'name': 'Homer'}, {'age': 10, 'name': 'Bart'}]