Python - 在一行中将多个字典值分配给不同的变量

Question

我有以下代码(顺便说一句，它会产生语法错误)。有人可以帮助我修复它，以便我可以获得产生预期结果的版本吗？

al = [{'a': 1, 'b': 2, 'c': 3}, {'a': 4, 'b': 5, 'c': 6}, {'a': 7, 'b': 8, 'c': 9}, {'a': 10, 'b': 11, 'c': 12}]
a, b, c = [i.a, i.b, i.c for i in al]

预期结果:

a = [1, 4, 7, 10]
b = [2, 5, 8, 11]
c = [3, 6, 9, 12]

Answer 1

如果你事先知道 key :

>>> al = [{'a': 1, 'b': 2, 'c': 3}, {'a': 4, 'b': 5, 'c': 6}, {'a': 7, 'b': 8, 'c': 9}, {'a': 10, 'b': 11, 'c': 12}]
>>> a, b, c = [[d[key] for d in al] for key in 'abc'] # ('a', 'b', 'c')
>>> a
[1, 4, 7, 10]
>>> b
[2, 5, 8, 11]
>>> c
[3, 6, 9, 12]

如果您事先不知道 key :

>>> d = {key: [d[key] for d in al] for key in al[0]}
>>> d
{'a': [1, 4, 7, 10], 'c': [3, 6, 9, 12], 'b': [2, 5, 8, 11]}
>>> a, b, c = map(d.get, 'abc') # OR map(d.get, ('a', 'b', 'c'))
>>> a
[1, 4, 7, 10]
>>> b
[2, 5, 8, 11]
>>> c
[3, 6, 9, 12]