访问 Python 列表中的字典

Question

我有一个列表，其中包含这样的字典：

json_obj = [[{'id': None},{'id': '5b98d01c0835f23f538cdcab'},{'id': '5b98d0440835f23f538cdcad'},{'id': '5b98d0ce0835f23f538cdcb9'}],[{'id': None},{'id': '5b98d01c0835f23f538cd'},{'id': '5b98d0440835f23f538cd'},{'id': '5b98d0ce0835f23f538cdc'}]]

我希望它存储在这样的列表列表中：

y=[['None','5b98d01c0835f23f538cdcab','5b98d0440835f23f538cdcad','5b98d0ce0835f23f538cdcb9'],['None','5b98d01c0835f23f538cd','5b98d0440835f23f538cd','5b98d0ce0835f23f538cdc']]

为了从我尝试过的字典中读取 id

for d in json_obj:

    print(d['id'])

但是我在上面的代码中看到了这个错误：

TypeError: list indices must be integers or slices, not str

Answer 1

您有一个嵌套的列表列表。有时有助于明显地观察这一点，注意嵌套[]语法：json_obj = [[{'id': None}, {'id': 'abc'}, {'id': 'def'}, {'id': 'ghi'}],            [{'id': None}, {'id': 'jkl'}, {'id': 'mno'}, {'id': 'pqr'}]]您的语法适用于单个列表：json_obj = [{'id': None}, {'id': 'abc'}, {'id': 'def'}, {'id': 'ghi'},            {'id': None}, {'id': 'jkl'}, {'id': 'mno'}, {'id': 'pqr'}]for d in json_obj:    print(d['id'])对于嵌套列表，您可以使用itertools.chain.from_iterable标准库中的：json_obj = [[{'id': None}, {'id': 'abc'}, {'id': 'def'}, {'id': 'ghi'}],            [{'id': None}, {'id': 'jkl'}, {'id': 'mno'}, {'id': 'pqr'}]]from itertools import chainfor d in chain.from_iterable(json_obj):    print(d['id'])或者，如果没有导入，您可以使用嵌套for循环：for L in json_obj:    for d in L:        print(d['id'])

Answer 2

使用嵌套列表理解。json_obj = [[{'id': None},{'id': '5b98d01c0835f23f538cdcab'},{'id': '5b98d0440835f23f538cdcad'},{'id': '5b98d0ce0835f23f538cdcb9'}],[{'id': None},{'id': '5b98d01c0835f23f538cd'},{'id': '5b98d0440835f23f538cd'},{'id': '5b98d0ce0835f23f538cdc'}]]print( [[j["id"] for j in i] for i in json_obj] )或者for i in json_obj:    for j in i:        print(j["id"])输出：[[None, '5b98d01c0835f23f538cdcab', '5b98d0440835f23f538cdcad', '5b98d0ce0835f23f538cdcb9'], [None, '5b98d01c0835f23f538cd', '5b98d0440835f23f538cd', '5b98d0ce0835f23f538cdc']]