分析Python处理基本数据<三>

来源：互联网发布：java参数传递引用传递编辑：程序博客网时间：2024/06/05 02:03

先贴上代码

#6 该文本里，输出在每一天发表tweets最多的用户dateline_by_user = {k:dict() for k in lines_by_created}for line in lines:    dateline = line[keys['created_at']].split(' ')[0]    username = line[keys['username']]    if dateline_by_user[dateline].has_key(username):        dateline_by_user[dateline][username] += 1    else:        dateline_by_user[dateline][username] = 1for k,v in dateline_by_user.items():    us = v.items()    us.sort(key=lambda k:k[1],reverse=True)    dateline_by_user[k] = {us[0][0]:us[0][1]}assert type(dateline_by_user) == dict

has_key的用法

# 如果给定的键在字典中可用返回True，否则返回FalseD = {'liu': '牛'}print D. has_key('liu')print D. has_key('牛')<pre name="code" class="python">TrueFalse

字典中各部分的类型

<pre name="code" class="python"># 字典中的key，value，itemsA = {'a': 1, 'b': 2, 'c': 3, 'd': 4}B = A.values()C = A.keys()D = A.items()E = D[0]print A, type(A)print B, type(B)print C, type(C)print D, type(D)print E, type(E)

{'a': 1, 'c': 3, 'b': 2, 'd': 4} <type 'dict'>[1, 3, 2, 4] <type 'list'>['a', 'c', 'b', 'd'] <type 'list'>[('a', 1), ('c', 3), ('b', 2), ('d', 4)] <type 'list'>('a', 1) <type 'tuple'>

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