字典列表 Python：如果现有的键、值对匹配，则将新的键、值对附加到字典

Question

original_list = [{"record1": 1, "record2": "loremipsum1", "record3": "loremipsum2", "record4": "loremipsum3"}, 
{"record1": 2, "record2": "loremipsum4", "record3": "loremipsum5", "record4": "loremipsum6"}, 
{"record1": 3, "record2": "loremipsum7", "record3": "loremipsum8", "record4": "loremipsum9"}, 
{"record1": 4, "record2": "loremipsum10", "record3": "loremipsum12", "record4": "loremipsum13"}, 
{"record1": 5, "record2": "loremipsum11", "record3": "loremipsum12", "record4": "loremipsum13"}]

to_append = [{"record1": 1, "new_record": "new1"},
{"record1": 2, "new_record": "new2"}]

output = [{"record1": 1, "record2": "loremipsum1", "record3": "loremipsum2", "record4": "loremipsum3", "new_record": "new1"}, 
{"record1": 2, "record2": "loremipsum4", "record3": "loremipsum5", "record4": "loremipsum6", "new_record": "new2"}, 
{"record1": 3, "record2": "loremipsum7", "record3": "loremipsum8", "record4": "loremipsum9"}, 
{"record1": 4, "record2": "loremipsum10", "record3": "loremipsum12", "record4": "loremipsum13"}, 
{"record1": 5, "record2": "loremipsum11", "record3": "loremipsum12", "record4": "loremipsum13"}]

如果record1 字段的值相同，则输出是将new_record 附加到列表中的字典，如果new_record 不存在，则不执行任何操作。如果使用 itertools 会更好。

我尝试了一些解决方案，但仅当 new_record 存在时，它才会返回一个带有附加字典的数组 - 忽略所有其他字典。

有人可以帮忙吗？ TIA

Answer 1

您可以对照array_to_append 中的每个字典检查original_array 中的每个字典；如果您在任何特定对中找到 record1 之间的匹配项，则 update 是原来的匹配项：

for d1 in original_array:
    for d2 in array_to_append:
        if d1['record1'] == d2['record1']:
            d1.update(d2)

导致：

>>> original_array 
[{'record1': 1,
  'record2': 'loremipsum1',
  'record3': 'loremipsum2',
  'record4': 'loremipsum3',
  'new_record': 'new1'},
 {'record1': 2,
  'record2': 'loremipsum4',
  'record3': 'loremipsum5',
  'record4': 'loremipsum6',
  'new_record': 'new2'},
 {'record1': 3,
  'record2': 'loremipsum7',
  'record3': 'loremipsum8',
  'record4': 'loremipsum9'},
 {'record1': 4,
  'record2': 'loremipsum10',
  'record3': 'loremipsum12',
  'record4': 'loremipsum13'},
 {'record1': 5,
  'record2': 'loremipsum11',
  'record3': 'loremipsum12',
  'record4': 'loremipsum13'}]

需要注意的几点：

• 这是在修改 original_array 和里面的字典，而不是创建新对象。
• 如果任何字典没有'record1' 键，则会引发KeyError。如果您希望某些字典没有该字段，则必须添加对该字段的处理。
• 如果array_to_append 中有多个条目与给定字典匹配的'record1'，则可能会遇到“new_records”相互覆盖的问题。