Question

我需要有效地拥有一个差异字典，该差异字典告诉我某个主字典与当前某个时刻之间的区别。

我需要有更改内容的完整路径，而不仅仅是更改的值。

例如：

primary_dict = {'a': 5, 'b':{'c': 9}, 'd':10}

和将会是

diff_dict = {'a':6, 'b':{'c':8}}

表示目前

primary_dict = {'a':6, 'b':{'c':8}, 'd':10}

当将值添加到字典时，我可以创建差异

我在线上看过，但是只发现两个字典之间的比较，效率不高，因为我需要比较的字典很大，保存了2次，然后递归比较所有，似乎对当前的问题大有帮助

编辑：将问题更改为更重要。就像我收到通知一样，反映我需要的问题是：如何在不创建新变量的情况下随时间更改字典？感谢@CristiFati和@Vishnudev的更正

Answer 1

使用dictdiffer库

>>> from dictdiffer import diff
>>> before_change = {'a': 5, 'b':{'c': 9}, 'd':10}
>>> after_change = {'a': 6, 'b':{'c':8, 'd': 10}, 'd':10}
>>> list(diff(before_change, after_change))
[('change', 'a', (5, 6)), ('change', 'b.c', (9, 8)), ('add', 'b', [('d', 10)])]

对于已删除的密钥，

>>> before_change = {'a': 5, 'b':{'c': 9}, 'd':10}
>>> after_change = {'a': 6, 'b':{'d': 10}, 'd':10}
>>> list(diff(before_change, after_change))
[('change', 'a', (5, 6)), ('add', 'b', [('d', 10)]), ('remove', 'b', [('c', 9)])]

Answer 2

OOPS也许可以解决。

该词典只能由具有创建更改记录的公共功能进行编辑。

Answer 3

复杂的解决方案（基于set操作和递归函数），用于扩展的复杂输入字典：

正如标题所述，感兴趣的条件是“当插入值时” 。

# extended input samples
before_change = {'a': 5, 'b': {'c': 9}, 'd': 10, 'g': {'h': {'k': 100}}}
after_change = {'a': 6, 'b': {'c': 9, 'f': 1}, 'd': 10, 'g': {'h': {'k': 300}}, 'e': 11}


def dict_diff(before, after):
    """Compute difference between dictionaries.
       Fetchs path to the innermost changed item"""

    new_keys = set(before) ^ set(after)
    diff = {k: after[k] for k in new_keys} # detecting new keys/items beforehand

    for k in set(before) & set(after):  # process intersected keys
        if before[k] != after[k]:
            if type(before[k]) is dict and type(after[k]) is dict:
                inner_diff = dict_diff(before[k], after[k])
                if inner_diff: diff[k] = inner_diff
            else:
                diff[k] = after[k]
    return diff

print(dict_diff(before_change, after_change))

输出：

{'e': 11, 'b': {'f': 1}, 'g': {'h': {'k': 300}}, 'a': 6}

Answer 4

已经存在类似的问题：[SO]: How to get the difference between two dictionaries in Python?。
您可以使用递归方法。

code.py ：

#!/usr/bin/env python3

import sys


def dummy_dict_diff(initial, final):
    ret = dict()
    for final_key, final_val in final.items():
        if final_key not in initial:  # Handle new keys
            ret[final_key] = final_val
            continue
        initial_val = initial[final_key]
        if final_val != initial_val:
            if type(final_val) != type(initial_val):
                ret[final_key] = final_val
            elif isinstance(final_val, (dict,)):
                ret[final_key] = dummy_dict_diff(initial_val, final_val)
            elif isinstance(final_val, (list, tuple)):
                ret[final_key] = final_val  # This would also require sequence diffs
            else:
                ret[final_key] = final_val
    deleted_keys = [item for item in initial if item not in final]  # Deleted keys
    for deleted_key in deleted_keys:
        ret[deleted_key] = initial[deleted_key]
    return ret


def main():
    before = {
        "a": 5,
        "b": {
            "c": 9
        },
        "d": 10
    }

    after = {
        "a": 6,
        "b": {
            "c": 8
        },
        "d": 10
    }

    print("Difference: {:}".format(dummy_dict_diff(before, after)))


if __name__ == "__main__":
    print("Python {:s} on {:s}\n".format(sys.version, sys.platform))
    main()
    print("\nDone.")

注释：

有些情况目前尚未处理。处理它们将需要更多代码（因此效果也会更慢）：
1. 序列（例如 list ， tuple ）值。现在，这是最终值（默认情况）

输出：

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q056617962]> "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\Scripts\python.exe" code.py
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] on win32

Difference: {'a': 6, 'b': {'c': 8}}

Done.

Answer 5

您可以使用理解词典：

actual_dict = {'a': 5, 'b':{'c': 9}, 'd':10}
diff_dict = {'a':6, 'b':{'c':8}}

primary_dict = {x: actual_dict[x] if x not in diff_dict.keys() else diff_dict[x] for x in actual_dict.keys()}

print(primary_dict)

输出：

{'a'：6，'b'：{'c'：8}，'d'：10}

Answer 6

您可以使用以下python代码获取两个字典之间的区别：

before_change = {'a': 5, 'b':{'c': 9}, 'd':10}
after_change = {'a': 6, 'b':{'c':8}, 'd':10}

bc_values = list(before_change.values())
ac_values = list(after_change.values())
ac_keys = list(after_change.keys())

for item in range(len(bc_values)):
 if ac_values[item] == bc_values[item] :
   after_change.pop(ac_keys[item])

print(after_change)

此代码的输出是：

{'a': 6, 'b': {'c': 8}}

插入值时如何存储字典的差异？

6 个答案: