python字典如何判断是否存在某个值_如何检查值是否存在于字典(python)

>>> d = {'1': 'one', '3': 'three', '2': 'two', '5': 'five', '4': 'four'}

>>> 'one' in d.values()

True

出于好奇，一些比较时间：

>>> T(lambda : 'one' in d.itervalues()).repeat()

[0.28107285499572754, 0.29107213020324707, 0.27941107749938965]

>>> T(lambda : 'one' in d.values()).repeat()

[0.38303399085998535, 0.37257885932922363, 0.37096405029296875]

>>> T(lambda : 'one' in d.viewvalues()).repeat()

[0.32004380226135254, 0.31716084480285645, 0.3171098232269287]

编辑：如果你想知道为什么…原因是上述每个返回一个不同类型的对象，这可能或可能不适合查找操作：

>>> type(d.viewvalues())

>>> type(d.values())

>>> type(d.itervalues())

EDIT2：根据评论中的请求…

>>> T(lambda : 'four' in d.itervalues()).repeat()

[0.41178202629089355, 0.3959040641784668, 0.3970959186553955]

>>> T(lambda : 'four' in d.values()).repeat()

[0.4631338119506836, 0.43541407585144043, 0.4359898567199707]

>>> T(lambda : 'four' in d.viewvalues()).repeat()

[0.43414998054504395, 0.4213531017303467, 0.41684913635253906]