from operator import itemgetter #itemgetter用来去dict中的key,省去了使用lambda函数 from itertools import groupby #itertool还包含有其他很多函数,比如将多个list联合起来。。 d1={‘name‘:‘zhangsan‘,‘age‘:20,‘country‘:‘China‘} d2={‘name‘:‘wangwu‘,‘age‘:19,‘country‘:‘USA‘} d3={‘name‘:‘lisi‘,‘age‘:22,‘country‘:‘JP‘} d4={‘name‘:‘zhaoliu‘,‘age‘:22,‘country‘:‘USA‘} d5={‘name‘:‘pengqi‘,‘age‘:22,‘country‘:‘USA‘} d6={‘name‘:‘lijiu‘,‘age‘:22,‘country‘:‘China‘} lst=[d1,d2,d3,d4,d5,d6] #通过country进行分组: lst.sort(key=itemgetter(‘country‘)) #需要先排序,然后才能groupby。lst排序后自身被改变 lstg = groupby(lst,itemgetter(‘country‘)) #lstg = groupby(lst,key=lambda x:x[‘country‘]) 等同于使用itemgetter() for key,group in lstg: for g in group: #group是一个迭代器,包含了所有的分组列表 print key,g 返回: China {‘country‘: ‘China‘, ‘age‘: 20, ‘name‘: ‘zhangsan‘} China {‘country‘: ‘China‘, ‘age‘: 22, ‘name‘: ‘lijiu‘} JP {‘country‘: ‘JP‘, ‘age‘: 22, ‘name‘: ‘lisi‘} USA {‘country‘: ‘USA‘, ‘age‘: 19, ‘name‘: ‘wangwu‘} USA {‘country‘: ‘USA‘, ‘age‘: 22, ‘name‘: ‘zhaoliu‘} USA {‘country‘: ‘USA‘, ‘age‘: 22, ‘name‘: ‘pengqi‘} print [key for key,group in lstg] #返回:[‘China‘, ‘JP‘, ‘USA‘] print [(key,list(group)) for key,group in lstg] #返回的list中包含着三个元组: [(‘China‘, [{‘country‘: ‘China‘, ‘age‘: 20, ‘name‘: ‘zhangsan‘}, {‘country‘: ‘China‘, ‘age‘: 22, ‘name‘: ‘lijiu‘}]), (‘JP‘, [{‘country‘: ‘JP‘, ‘age‘: 22, ‘name‘: ‘lisi‘}]), (‘USA‘, [{‘country‘: ‘USA‘, ‘age‘: 19, ‘name‘: ‘wangwu‘}, {‘country‘: ‘USA‘, ‘age‘: 22, ‘name‘: ‘zhaoliu‘}, {‘country‘: ‘USA‘, ‘age‘: 22, ‘name‘: ‘pengqi‘}])] print dict([(key,list(group)) for key,group in lstg]) #返回的是一个字典: {‘JP‘: [{‘country‘: ‘JP‘, ‘age‘: 22, ‘name‘: ‘lisi‘}], ‘China‘: [{‘country‘: ‘China‘, ‘age‘: 20, ‘name‘: ‘zhangsan‘}, {‘country‘: ‘China‘, ‘age‘: 22, ‘name‘: ‘lijiu‘}], ‘USA‘: [{‘country‘: ‘USA‘, ‘age‘: 19, ‘name‘: ‘wangwu‘}, {‘country‘: ‘USA‘, ‘age‘: 22, ‘name‘: ‘zhaoliu‘}, {‘country‘: ‘USA‘, ‘age‘: 22, ‘name‘: ‘pengqi‘}]} print dict([(key,len(list(group))) for key,group in lstg]) #返回每个分组的个数: {‘JP‘: 1, ‘China‘: 2, ‘USA‘: 3}
#返回包含有2个以上元素的分组 print [key for key,group in groupby(sorted(lst,key=itemgetter(‘country‘)),itemgetter(‘country‘)) if len(list(group))>=2] #返回:[‘China‘, ‘USA‘]
时间: 2024-10-13 16:29:34