Question

给出dictionary：

sql_playlists={
'user1':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 1': 1.0},
'user2':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 2': 1.0},
'user3':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 3': 1.0},
'user4':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 4': 1.0},
'user5':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 4': 1.0}}

我可以像这样创建keys和values的数据元组：

sqltuples = [(k1,k2,v2) for k1,v1 in sql_playlists.items()
             for k2,v2 in v1.items()]

输出：

[(u'user1', u'Make You Feel My Love', 1.0), (u'user1', u'I See Fire', 1.0), (u'user', u'High And Dry', 1.0), (u'user1', u'Fake Plastic Trees', 1.0), (u'user1', u'One', 1.0), (u'user1', u'Goodbye My Lover', 1.0), (u'user1', u'No Surprises', 1.0)]

为每个用户。

但是如果sql_playlist是list，相同的数据结构但在[]内，而不是dictionary会怎样？

编辑：列表

sql_playlists=[{
'user1':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 1': 1.0},
'user2':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 2': 1.0},
'user3':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 3': 1.0},
'user4':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 4': 1.0},
'user5':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 4': 1.0}}]

如何调整list comprehension以便从列表中生成相同的tuples？

这适用于第一个用户：

sqltuples = [(k1,k2,v2) for k1,v1 in sql_playlists[0].items()
             for k2,v2 in v1.items()]

但我想要所有用户。

Answer 1

如果你的意思是字典数组： sql_playlists=[ {'user1':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 1': 1.0}}, {'user2':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 2': 1.0}}, {'user3':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 3': 1.0}}, {'user4':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 4': 1.0}}, {'user5':{'Karma Police':1.0,'Roxanne':1.0,'Sonnet':1.0,'We Will Rock You':1.0,'Song 4': 1.0}}]

然后：

sqltuples = [(k1,k2,v2) for vlist in sql_playlists for k1,v1 in vlist.items() for k2,v2 in v1.items()]

你应该注意，这将以不同的顺序产生元组，因为在枚举列表而不是dicts时保留了排序

Python - 从列表中创建元组

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