问题:更新嵌套深度不同的字典的值

我正在寻找一种方法来用字典更新内容覆盖字典字典A

dictionary1={'level1':{'level2':{'levelA':0,'levelB':1}}}
update={'level1':{'level2':{'levelB':10}}}
dictionary1.update(update)
print dictionary1
{'level1': {'level2': {'levelB': 10}}}

我知道update会删除level2中的值,因为它正在更新最低的密钥level1。

鉴于dictionary1和update可以有任何长度,我该如何解决?

I’m looking for a way to update dict dictionary1 with the contents of dict update wihout overwriting levelA

dictionary1={'level1':{'level2':{'levelA':0,'levelB':1}}}
update={'level1':{'level2':{'levelB':10}}}
dictionary1.update(update)
print dictionary1
{'level1': {'level2': {'levelB': 10}}}

I know that update deletes the values in level2 because it’s updating the lowest key level1.

How could I tackle this, given that dictionary1 and update can have any length?


回答 0

@FM的答案具有正确的总体思路,即递归解决方案,但有些特殊的编码和至少一个错误。我建议改为:

Python 2:

import collections

def update(d, u):
    for k, v in u.iteritems():
        if isinstance(v, collections.Mapping):
            d[k] = update(d.get(k, {}), v)
        else:
            d[k] = v
    return d

Python 3:

import collections.abc

def update(d, u):
    for k, v in u.items():
        if isinstance(v, collections.abc.Mapping):
            d[k] = update(d.get(k, {}), v)
        else:
            d[k] = v
    return d

该错误显示当“更新”拥有了kv项目在那里vdictk最初不是被更新在字典中的关键- @ FM代码“跳过”更新的这一部分(因为它执行它的新的空dict其不会在任何地方保存或返回,而是在递归调用返回时丢失)。

我的其他改动很小:没有理由让if/ else构造何时.get更快,更干净地完成相同的工作,并且isinstance为了通用起见,最好将其应用于抽象基类(而不是具体的基类)。

@FM’s answer has the right general idea, i.e. a recursive solution, but somewhat peculiar coding and at least one bug. I’d recommend, instead:

Python 2:

import collections

def update(d, u):
    for k, v in u.iteritems():
        if isinstance(v, collections.Mapping):
            d[k] = update(d.get(k, {}), v)
        else:
            d[k] = v
    return d

Python 3:

import collections.abc

def update(d, u):
    for k, v in u.items():
        if isinstance(v, collections.abc.Mapping):
            d[k] = update(d.get(k, {}), v)
        else:
            d[k] = v
    return d

The bug shows up when the “update” has a k, v item where v is a dict and k is not originally a key in the dictionary being updated — @FM’s code “skips” this part of the update (because it performs it on an empty new dict which isn’t saved or returned anywhere, just lost when the recursive call returns).

My other changes are minor: there is no reason for the if/else construct when .get does the same job faster and cleaner, and isinstance is best applied to abstract base classes (not concrete ones) for generality.


回答 1

我花了一点时间,但是由于@Alex的帖子,他填补了我所缺少的空白。但是,如果递归中的值dict恰好是,我遇到了一个问题list,所以我认为我应该分享并扩展他的答案。

import collections

def update(orig_dict, new_dict):
    for key, val in new_dict.iteritems():
        if isinstance(val, collections.Mapping):
            tmp = update(orig_dict.get(key, { }), val)
            orig_dict[key] = tmp
        elif isinstance(val, list):
            orig_dict[key] = (orig_dict.get(key, []) + val)
        else:
            orig_dict[key] = new_dict[key]
    return orig_dict

Took me a little bit on this one, but thanks to @Alex’s post, he filled in the gap I was missing. However, I came across an issue if a value within the recursive dict happens to be a list, so I thought I’d share, and extend his answer.

import collections

def update(orig_dict, new_dict):
    for key, val in new_dict.iteritems():
        if isinstance(val, collections.Mapping):
            tmp = update(orig_dict.get(key, { }), val)
            orig_dict[key] = tmp
        elif isinstance(val, list):
            orig_dict[key] = (orig_dict.get(key, []) + val)
        else:
            orig_dict[key] = new_dict[key]
    return orig_dict

回答 2

@Alex的回答很好,但是用诸如的字典替换整数等元素时不起作用update({'foo':0},{'foo':{'bar':1}})。此更新解决了它:

import collections
def update(d, u):
    for k, v in u.iteritems():
        if isinstance(d, collections.Mapping):
            if isinstance(v, collections.Mapping):
                r = update(d.get(k, {}), v)
                d[k] = r
            else:
                d[k] = u[k]
        else:
            d = {k: u[k]}
    return d

update({'k1': 1}, {'k1': {'k2': {'k3': 3}}})

@Alex’s answer is good, but doesn’t work when replacing an element such as an integer with a dictionary, such as update({'foo':0},{'foo':{'bar':1}}). This update addresses it:

import collections
def update(d, u):
    for k, v in u.iteritems():
        if isinstance(d, collections.Mapping):
            if isinstance(v, collections.Mapping):
                r = update(d.get(k, {}), v)
                d[k] = r
            else:
                d[k] = u[k]
        else:
            d = {k: u[k]}
    return d

update({'k1': 1}, {'k1': {'k2': {'k3': 3}}})

回答 3

与已接受的解决方案相同,但更清晰的变量命名,文档字符串,并修复了一个错误,{}即不能覆盖值的错误。

import collections


def deep_update(source, overrides):
    """
    Update a nested dictionary or similar mapping.
    Modify ``source`` in place.
    """
    for key, value in overrides.iteritems():
        if isinstance(value, collections.Mapping) and value:
            returned = deep_update(source.get(key, {}), value)
            source[key] = returned
        else:
            source[key] = overrides[key]
    return source

以下是一些测试案例:

def test_deep_update():
    source = {'hello1': 1}
    overrides = {'hello2': 2}
    deep_update(source, overrides)
    assert source == {'hello1': 1, 'hello2': 2}

    source = {'hello': 'to_override'}
    overrides = {'hello': 'over'}
    deep_update(source, overrides)
    assert source == {'hello': 'over'}

    source = {'hello': {'value': 'to_override', 'no_change': 1}}
    overrides = {'hello': {'value': 'over'}}
    deep_update(source, overrides)
    assert source == {'hello': {'value': 'over', 'no_change': 1}}

    source = {'hello': {'value': 'to_override', 'no_change': 1}}
    overrides = {'hello': {'value': {}}}
    deep_update(source, overrides)
    assert source == {'hello': {'value': {}, 'no_change': 1}}

    source = {'hello': {'value': {}, 'no_change': 1}}
    overrides = {'hello': {'value': 2}}
    deep_update(source, overrides)
    assert source == {'hello': {'value': 2, 'no_change': 1}}

该功能在charlatan软件包的中提供charlatan.utils

Same solution as the accepted one, but clearer variable naming, docstring, and fixed a bug where {} as a value would not override.

import collections


def deep_update(source, overrides):
    """
    Update a nested dictionary or similar mapping.
    Modify ``source`` in place.
    """
    for key, value in overrides.iteritems():
        if isinstance(value, collections.Mapping) and value:
            returned = deep_update(source.get(key, {}), value)
            source[key] = returned
        else:
            source[key] = overrides[key]
    return source

Here are a few test cases:

def test_deep_update():
    source = {'hello1': 1}
    overrides = {'hello2': 2}
    deep_update(source, overrides)
    assert source == {'hello1': 1, 'hello2': 2}

    source = {'hello': 'to_override'}
    overrides = {'hello': 'over'}
    deep_update(source, overrides)
    assert source == {'hello': 'over'}

    source = {'hello': {'value': 'to_override', 'no_change': 1}}
    overrides = {'hello': {'value': 'over'}}
    deep_update(source, overrides)
    assert source == {'hello': {'value': 'over', 'no_change': 1}}

    source = {'hello': {'value': 'to_override', 'no_change': 1}}
    overrides = {'hello': {'value': {}}}
    deep_update(source, overrides)
    assert source == {'hello': {'value': {}, 'no_change': 1}}

    source = {'hello': {'value': {}, 'no_change': 1}}
    overrides = {'hello': {'value': 2}}
    deep_update(source, overrides)
    assert source == {'hello': {'value': 2, 'no_change': 1}}

This functions is available in the charlatan package, in charlatan.utils.


回答 4

如果有人需要,这是递归字典合并的不可变版本。

基于@Alex Martelli的答案

Python 2.x:

import collections
from copy import deepcopy


def merge(dict1, dict2):
    ''' Return a new dictionary by merging two dictionaries recursively. '''

    result = deepcopy(dict1)

    for key, value in dict2.iteritems():
        if isinstance(value, collections.Mapping):
            result[key] = merge(result.get(key, {}), value)
        else:
            result[key] = deepcopy(dict2[key])

    return result

Python 3.x:

import collections
from copy import deepcopy


def merge(dict1, dict2):
    ''' Return a new dictionary by merging two dictionaries recursively. '''

    result = deepcopy(dict1)

    for key, value in dict2.items():
        if isinstance(value, collections.Mapping):
            result[key] = merge(result.get(key, {}), value)
        else:
            result[key] = deepcopy(dict2[key])

    return result

Here’s an Immutable version of recursive dictionary merge in case anybody needs it.

Based upon @Alex Martelli’s answer.

Python 3.x:

import collections
from copy import deepcopy


def merge(dict1, dict2):
    ''' Return a new dictionary by merging two dictionaries recursively. '''

    result = deepcopy(dict1)

    for key, value in dict2.items():
        if isinstance(value, collections.Mapping):
            result[key] = merge(result.get(key, {}), value)
        else:
            result[key] = deepcopy(dict2[key])

    return result

Python 2.x:

import collections
from copy import deepcopy


def merge(dict1, dict2):
    ''' Return a new dictionary by merging two dictionaries recursively. '''

    result = deepcopy(dict1)

    for key, value in dict2.iteritems():
        if isinstance(value, collections.Mapping):
            result[key] = merge(result.get(key, {}), value)
        else:
            result[key] = deepcopy(dict2[key])

    return result

回答 5

@Alex的答案进行了较小的改进,可以更新深度不同的字典,并限制了更新深入原始嵌套词典的深度(但更新词典的深度不受限制)。仅测试了少数情况:

def update(d, u, depth=-1):
    """
    Recursively merge or update dict-like objects. 
    >>> update({'k1': {'k2': 2}}, {'k1': {'k2': {'k3': 3}}, 'k4': 4})
    {'k1': {'k2': {'k3': 3}}, 'k4': 4}
    """

    for k, v in u.iteritems():
        if isinstance(v, Mapping) and not depth == 0:
            r = update(d.get(k, {}), v, depth=max(depth - 1, -1))
            d[k] = r
        elif isinstance(d, Mapping):
            d[k] = u[k]
        else:
            d = {k: u[k]}
    return d

Minor improvements to @Alex’s answer that enables updating of dictionaries of differing depths as well as limiting the depth that the update dives into the original nested dictionary (but the updating dictionary depth is not limited). Only a few cases have been tested:

def update(d, u, depth=-1):
    """
    Recursively merge or update dict-like objects. 
    >>> update({'k1': {'k2': 2}}, {'k1': {'k2': {'k3': 3}}, 'k4': 4})
    {'k1': {'k2': {'k3': 3}}, 'k4': 4}
    """

    for k, v in u.iteritems():
        if isinstance(v, Mapping) and not depth == 0:
            r = update(d.get(k, {}), v, depth=max(depth - 1, -1))
            d[k] = r
        elif isinstance(d, Mapping):
            d[k] = u[k]
        else:
            d = {k: u[k]}
    return d

回答 6

这个问题很旧,但是我在寻找“深度合并”解决方案时就落在了这里。上面的答案启发了接下来的事情。我最终写了我自己的,因为我测试的所有版本中都有错误。错过的临界点是,在两个输入字典的任意深度处,对于某个键k,当d [k]或u [k] 不是字典时的决策树是错误的。

而且,此解决方案不需要递归,这与dict.update()工作方式和return 更加对称None

import collections
def deep_merge(d, u):
   """Do a deep merge of one dict into another.

   This will update d with values in u, but will not delete keys in d
   not found in u at some arbitrary depth of d. That is, u is deeply
   merged into d.

   Args -
     d, u: dicts

   Note: this is destructive to d, but not u.

   Returns: None
   """
   stack = [(d,u)]
   while stack:
      d,u = stack.pop(0)
      for k,v in u.items():
         if not isinstance(v, collections.Mapping):
            # u[k] is not a dict, nothing to merge, so just set it,
            # regardless if d[k] *was* a dict
            d[k] = v
         else:
            # note: u[k] is a dict

            # get d[k], defaulting to a dict, if it doesn't previously
            # exist
            dv = d.setdefault(k, {})

            if not isinstance(dv, collections.Mapping):
               # d[k] is not a dict, so just set it to u[k],
               # overriding whatever it was
               d[k] = v
            else:
               # both d[k] and u[k] are dicts, push them on the stack
               # to merge
               stack.append((dv, v))

This question is old, but I landed here when searching for a “deep merge” solution. The answers above inspired what follows. I ended up writing my own because there were bugs in all the versions I tested. The critical point missed was, at some arbitrary depth of the two input dicts, for some key, k, the decision tree when d[k] or u[k] is not a dict was faulty.

Also, this solution does not require recursion, which is more symmetric with how dict.update() works, and returns None.

import collections
def deep_merge(d, u):
   """Do a deep merge of one dict into another.

   This will update d with values in u, but will not delete keys in d
   not found in u at some arbitrary depth of d. That is, u is deeply
   merged into d.

   Args -
     d, u: dicts

   Note: this is destructive to d, but not u.

   Returns: None
   """
   stack = [(d,u)]
   while stack:
      d,u = stack.pop(0)
      for k,v in u.items():
         if not isinstance(v, collections.Mapping):
            # u[k] is not a dict, nothing to merge, so just set it,
            # regardless if d[k] *was* a dict
            d[k] = v
         else:
            # note: u[k] is a dict

            # get d[k], defaulting to a dict, if it doesn't previously
            # exist
            dv = d.setdefault(k, {})

            if not isinstance(dv, collections.Mapping):
               # d[k] is not a dict, so just set it to u[k],
               # overriding whatever it was
               d[k] = v
            else:
               # both d[k] and u[k] are dicts, push them on the stack
               # to merge
               stack.append((dv, v))

回答 7

只需使用python-benedict (我做到了),它就有一个merge(deepupdate)实用程序方法和许多其他方法。它与python 2 / python 3一起工作,并且经过了良好的测试。

from benedict import benedict

dictionary1=benedict({'level1':{'level2':{'levelA':0,'levelB':1}}})
update={'level1':{'level2':{'levelB':10}}}
dictionary1.merge(update)
print(dictionary1)
# >> {'level1':{'level2':{'levelA':0,'levelB':10}}}

安装: pip install python-benedict

文档:https : //github.com/fabiocaccamo/python-benedict

Just use python-benedict (I did it), it has a merge (deepupdate) utility method and many others. It works with python 2 / python 3 and it is well tested.

from benedict import benedict

dictionary1=benedict({'level1':{'level2':{'levelA':0,'levelB':1}}})
update={'level1':{'level2':{'levelB':10}}}
dictionary1.merge(update)
print(dictionary1)
# >> {'level1':{'level2':{'levelA':0,'levelB':10}}}

Installation: pip install python-benedict

Documentation: https://github.com/fabiocaccamo/python-benedict

Note: I am the author of this project


回答 8

在这两个答案中,作者似乎都没有理解更新字典中存储的对象,甚至迭代字典项(与键相对)的概念。因此,我不得不写一篇不会造成毫无意义的重言式字典存储和检索的书。假定这些字典存储其他字典或简单类型。

def update_nested_dict(d, other):
    for k, v in other.items():
        if isinstance(v, collections.Mapping):
            d_v = d.get(k)
            if isinstance(d_v, collections.Mapping):
                update_nested_dict(d_v, v)
            else:
                d[k] = v.copy()
        else:
            d[k] = v

或更简单的一种适用于任何类型的:

def update_nested_dict(d, other):
    for k, v in other.items():
        d_v = d.get(k)
        if isinstance(v, collections.Mapping) and isinstance(d_v, collections.Mapping):
            update_nested_dict(d_v, v)
        else:
            d[k] = deepcopy(v) # or d[k] = v if you know what you're doing

In neither of these answers the authors seem to understand the concept of updating an object stored in a dictionary nor even of iterating over dictionary items (as opposed to keys). So I had to write one which doesn’t make pointless tautological dictionary stores and retrievals. The dicts are assumed to store other dicts or simple types.

def update_nested_dict(d, other):
    for k, v in other.items():
        if isinstance(v, collections.Mapping):
            d_v = d.get(k)
            if isinstance(d_v, collections.Mapping):
                update_nested_dict(d_v, v)
            else:
                d[k] = v.copy()
        else:
            d[k] = v

Or even simpler one working with any type:

def update_nested_dict(d, other):
    for k, v in other.items():
        d_v = d.get(k)
        if isinstance(v, collections.Mapping) and isinstance(d_v, collections.Mapping):
            update_nested_dict(d_v, v)
        else:
            d[k] = deepcopy(v) # or d[k] = v if you know what you're doing

回答 9

更新@Alex Martelli的答案以修复其代码中的错误,以使解决方案更可靠:

def update_dict(d, u):
    for k, v in u.items():
        if isinstance(v, collections.Mapping):
            default = v.copy()
            default.clear()
            r = update_dict(d.get(k, default), v)
            d[k] = r
        else:
            d[k] = v
    return d

关键是我们经常想在递归时创建相同的类型,因此在这里我们使用v.copy().clear()not {}。如果这是可以具有不同类型s dict的类型collections.defaultdict,则这特别有用default_factory

另请注意,u.iteritems()已将更改为u.items()中的Python3

Update to @Alex Martelli’s answer to fix a bug in his code to make the solution more robust:

def update_dict(d, u):
    for k, v in u.items():
        if isinstance(v, collections.Mapping):
            default = v.copy()
            default.clear()
            r = update_dict(d.get(k, default), v)
            d[k] = r
        else:
            d[k] = v
    return d

The key is that we often want to create the same type at recursion, so here we use v.copy().clear() but not {}. And this is especially useful if the dict here is of type collections.defaultdict which can have different kinds of default_factorys.

Also notice that the u.iteritems() has been changed to u.items() in Python3.


回答 10

我使用了@Alex Martelli建议的解决方案,但失败了

TypeError 'bool' object does not support item assignment

当两个字典在某种程度上数据类型不同时。

在相同级别的情况下,字典的元素d只是一个标量(即Bool),而字典的元素u仍然是字典,则重新分配失败,因为无法将字典分配到标量中(如True[k])。

一个附加条件修复了:

from collections import Mapping

def update_deep(d, u):
    for k, v in u.items():
        # this condition handles the problem
        if not isinstance(d, Mapping):
            d = u
        elif isinstance(v, Mapping):
            r = update_deep(d.get(k, {}), v)
            d[k] = r
        else:
            d[k] = u[k]

    return d

I used the solution @Alex Martelli suggests, but it fails

TypeError 'bool' object does not support item assignment

when the two dictionaries differ in data type at some level.

In case at the same level the element of dictionary d is just a scalar (ie. Bool) while the element of dictionary u is still dictionary the reassignment fails as no dictionary assignment is possible into scalar (like True[k]).

One added condition fixes that:

from collections import Mapping

def update_deep(d, u):
    for k, v in u.items():
        # this condition handles the problem
        if not isinstance(d, Mapping):
            d = u
        elif isinstance(v, Mapping):
            r = update_deep(d.get(k, {}), v)
            d[k] = r
        else:
            d[k] = u[k]

    return d

回答 11

下面的代码应update({'k1': 1}, {'k1': {'k2': 2}})以正确的方式解决@Alex Martelli的答案中的问题。

def deepupdate(original, update):
    """Recursively update a dict.

    Subdict's won't be overwritten but also updated.
    """
    if not isinstance(original, abc.Mapping):
        return update
    for key, value in update.items():
        if isinstance(value, abc.Mapping):
            original[key] = deepupdate(original.get(key, {}), value)
        else:
            original[key] = value
    return original

The code below should solve the update({'k1': 1}, {'k1': {'k2': 2}}) issue in @Alex Martelli’s answer the right way.

def deepupdate(original, update):
    """Recursively update a dict.

    Subdict's won't be overwritten but also updated.
    """
    if not isinstance(original, abc.Mapping):
        return update
    for key, value in update.items():
        if isinstance(value, abc.Mapping):
            original[key] = deepupdate(original.get(key, {}), value)
        else:
            original[key] = value
    return original

回答 12

def update(value, nvalue):
    if not isinstance(value, dict) or not isinstance(nvalue, dict):
        return nvalue
    for k, v in nvalue.items():
        value.setdefault(k, dict())
        if isinstance(v, dict):
            v = update(value[k], v)
        value[k] = v
    return value

使用dictcollections.Mapping

def update(value, nvalue):
    if not isinstance(value, dict) or not isinstance(nvalue, dict):
        return nvalue
    for k, v in nvalue.items():
        value.setdefault(k, dict())
        if isinstance(v, dict):
            v = update(value[k], v)
        value[k] = v
    return value

use dict or collections.Mapping


回答 13

我知道这个问题已经很老了,但是当我不得不更新嵌套字典时,仍然会发布我的操作。我们可以使用dict通过python中的引用传递的事实,假设键的路径是已知的并且是点分隔的。外汇,如果我们有一个名为data的字典:

{
"log_config_worker": {
    "version": 1, 
    "root": {
        "handlers": [
            "queue"
        ], 
        "level": "DEBUG"
    }, 
    "disable_existing_loggers": true, 
    "handlers": {
        "queue": {
            "queue": null, 
            "class": "myclass1.QueueHandler"
        }
    }
}, 
"number_of_archived_logs": 15, 
"log_max_size": "300M", 
"cron_job_dir": "/etc/cron.hourly/", 
"logs_dir": "/var/log/patternex/", 
"log_rotate_dir": "/etc/logrotate.d/"
}

而且我们要更新队列类,键的路径将是- log_config_worker.handlers.queue.class

我们可以使用以下函数来更新值:

def get_updated_dict(obj, path, value):
    key_list = path.split(".")

    for k in key_list[:-1]:
        obj = obj[k]

    obj[key_list[-1]] = value

get_updated_dict(data, "log_config_worker.handlers.queue.class", "myclass2.QueueHandler")

这样可以正确更新字典。

I know this question is pretty old, but still posting what I do when I have to update a nested dictionary. We can use the fact that dicts are passed by reference in python Assuming that the path of the key is known and is dot separated. Forex if we have a dict named data:

{
"log_config_worker": {
    "version": 1, 
    "root": {
        "handlers": [
            "queue"
        ], 
        "level": "DEBUG"
    }, 
    "disable_existing_loggers": true, 
    "handlers": {
        "queue": {
            "queue": null, 
            "class": "myclass1.QueueHandler"
        }
    }
}, 
"number_of_archived_logs": 15, 
"log_max_size": "300M", 
"cron_job_dir": "/etc/cron.hourly/", 
"logs_dir": "/var/log/patternex/", 
"log_rotate_dir": "/etc/logrotate.d/"
}

And we want to update the queue class, the path of the key would be – log_config_worker.handlers.queue.class

We can use the following function to update the value:

def get_updated_dict(obj, path, value):
    key_list = path.split(".")

    for k in key_list[:-1]:
        obj = obj[k]

    obj[key_list[-1]] = value

get_updated_dict(data, "log_config_worker.handlers.queue.class", "myclass2.QueueHandler")

This would update the dictionary correctly.


回答 14

可能是您偶然发现了像今天这样的非标准词典,该词典没有iteritems-Attribute。在这种情况下,很容易将这种类型的词典解释为标准词典。例如: Python 2.7:

    import collections
    def update(orig_dict, new_dict):
        for key, val in dict(new_dict).iteritems():
            if isinstance(val, collections.Mapping):
                tmp = update(orig_dict.get(key, { }), val)
                orig_dict[key] = tmp
            elif isinstance(val, list):
                orig_dict[key] = (orig_dict[key] + val)
            else:
                orig_dict[key] = new_dict[key]
        return orig_dict

    import multiprocessing
    d=multiprocessing.Manager().dict({'sample':'data'})
    u={'other': 1234}

    x=update(d, u)
    x.items()

Python 3.8:

    def update(orig_dict, new_dict):
        orig_dict=dict(orig_dict)
        for key, val in dict(new_dict).items():
            if isinstance(val, collections.abc.Mapping):
                tmp = update(orig_dict.get(key, { }), val)
                orig_dict[key] = tmp
            elif isinstance(val, list):
                orig_dict[key] = (orig_dict[key] + val)
            else:
                orig_dict[key] = new_dict[key]
        return orig_dict

    import collections
    import multiprocessing
    d=multiprocessing.Manager().dict({'sample':'data'})
    u={'other': 1234, "deeper": {'very': 'deep'}}

    x=update(d, u)
    x.items()

It could be that you stumble over a non-standard-dictionary, like me today, which has no iteritems-Attribute. In this case it’s easy to interpret this type of dictionary as a standard-dictionary. E.g.: Python 2.7:

    import collections
    def update(orig_dict, new_dict):
        for key, val in dict(new_dict).iteritems():
            if isinstance(val, collections.Mapping):
                tmp = update(orig_dict.get(key, { }), val)
                orig_dict[key] = tmp
            elif isinstance(val, list):
                orig_dict[key] = (orig_dict[key] + val)
            else:
                orig_dict[key] = new_dict[key]
        return orig_dict

    import multiprocessing
    d=multiprocessing.Manager().dict({'sample':'data'})
    u={'other': 1234}

    x=update(d, u)
    x.items()

Python 3.8:

    def update(orig_dict, new_dict):
        orig_dict=dict(orig_dict)
        for key, val in dict(new_dict).items():
            if isinstance(val, collections.abc.Mapping):
                tmp = update(orig_dict.get(key, { }), val)
                orig_dict[key] = tmp
            elif isinstance(val, list):
                orig_dict[key] = (orig_dict[key] + val)
            else:
                orig_dict[key] = new_dict[key]
        return orig_dict

    import collections
    import multiprocessing
    d=multiprocessing.Manager().dict({'sample':'data'})
    u={'other': 1234, "deeper": {'very': 'deep'}}

    x=update(d, u)
    x.items()

回答 15

是! 和另一个解决方案。我的解决方案在要检查的键上有所不同。在所有其他解决方案中,我们仅查看中的键dict_b。但是这里我们看一下两个词典的结合。

随便做吧

def update_nested(dict_a, dict_b):
    set_keys = set(dict_a.keys()).union(set(dict_b.keys()))
    for k in set_keys:
        v = dict_a.get(k)
        if isinstance(v, dict):
            new_dict = dict_b.get(k, None)
            if new_dict:
                update_nested(v, new_dict)
        else:
            new_value = dict_b.get(k, None)
            if new_value:
                dict_a[k] = new_value

Yes! And another solution. My solution differs in the keys that are being checked. In all other solutions we only look at the keys in dict_b. But here we look in the union of both dictionaries.

Do with it as you please

def update_nested(dict_a, dict_b):
    set_keys = set(dict_a.keys()).union(set(dict_b.keys()))
    for k in set_keys:
        v = dict_a.get(k)
        if isinstance(v, dict):
            new_dict = dict_b.get(k, None)
            if new_dict:
                update_nested(v, new_dict)
        else:
            new_value = dict_b.get(k, None)
            if new_value:
                dict_a[k] = new_value

回答 16

如果要用数组替换“完全嵌套的字典”,可以使用以下代码段:

它将用“ new_value”替换任何“ old_value”。它大致在对字典进行深度优先的重建。它甚至可以与作为第一级输入参数的List或Str / int一起使用。

def update_values_dict(original_dict, future_dict, old_value, new_value):
    # Recursively updates values of a nested dict by performing recursive calls

    if isinstance(original_dict, Dict):
        # It's a dict
        tmp_dict = {}
        for key, value in original_dict.items():
            tmp_dict[key] = update_values_dict(value, future_dict, old_value, new_value)
        return tmp_dict
    elif isinstance(original_dict, List):
        # It's a List
        tmp_list = []
        for i in original_dict:
            tmp_list.append(update_values_dict(i, future_dict, old_value, new_value))
        return tmp_list
    else:
        # It's not a dict, maybe a int, a string, etc.
        return original_dict if original_dict != old_value else new_value

If you want to replace a “full nested dictionary with arrays” you can use this snippet :

It will replace any “old_value” by “new_value”. It’s roughly doing a depth-first rebuilding of the dictionary. It can even work with List or Str/int given as input parameter of first level.

def update_values_dict(original_dict, future_dict, old_value, new_value):
    # Recursively updates values of a nested dict by performing recursive calls

    if isinstance(original_dict, Dict):
        # It's a dict
        tmp_dict = {}
        for key, value in original_dict.items():
            tmp_dict[key] = update_values_dict(value, future_dict, old_value, new_value)
        return tmp_dict
    elif isinstance(original_dict, List):
        # It's a List
        tmp_list = []
        for i in original_dict:
            tmp_list.append(update_values_dict(i, future_dict, old_value, new_value))
        return tmp_list
    else:
        # It's not a dict, maybe a int, a string, etc.
        return original_dict if original_dict != old_value else new_value

回答 17

使用递归的另一种方法:

def updateDict(dict1,dict2):
    keys1 = list(dict1.keys())
    keys2= list(dict2.keys())
    keys2 = [x for x in keys2 if x in keys1]
    for x in keys2:
        if (x in keys1) & (type(dict1[x]) is dict) & (type(dict2[x]) is dict):
            updateDict(dict1[x],dict2[x])
        else:
            dict1.update({x:dict2[x]})
    return(dict1)

Another way of using recursion:

def updateDict(dict1,dict2):
    keys1 = list(dict1.keys())
    keys2= list(dict2.keys())
    keys2 = [x for x in keys2 if x in keys1]
    for x in keys2:
        if (x in keys1) & (type(dict1[x]) is dict) & (type(dict2[x]) is dict):
            updateDict(dict1[x],dict2[x])
        else:
            dict1.update({x:dict2[x]})
    return(dict1)

回答 18

一个新的Q如何通过钥匙链

dictionary1={'level1':{'level2':{'levelA':0,'levelB':1}},'anotherLevel1':{'anotherLevel2':{'anotherLevelA':0,'anotherLevelB':1}}}
update={'anotherLevel1':{'anotherLevel2':1014}}
dictionary1.update(update)
print dictionary1
{'level1':{'level2':{'levelA':0,'levelB':1}},'anotherLevel1':{'anotherLevel2':1014}}

a new Q how to By a keys chain

dictionary1={'level1':{'level2':{'levelA':0,'levelB':1}},'anotherLevel1':{'anotherLevel2':{'anotherLevelA':0,'anotherLevelB':1}}}
update={'anotherLevel1':{'anotherLevel2':1014}}
dictionary1.update(update)
print dictionary1
{'level1':{'level2':{'levelA':0,'levelB':1}},'anotherLevel1':{'anotherLevel2':1014}}

回答 19

您可以尝试一下,它可以与列表一起使用,而且很纯粹:

def update_keys(newd, dic, mapping):
  def upsingle(d,k,v):
    if k in mapping:
      d[mapping[k]] = v
    else:
      d[k] = v
  for ekey, evalue in dic.items():
    upsingle(newd, ekey, evalue)
    if type(evalue) is dict:
      update_keys(newd, evalue, mapping)
    if type(evalue) is list:
      upsingle(newd, ekey, [update_keys({}, i, mapping) for i in evalue])
  return newd

you could try this, it works with lists and is pure:

def update_keys(newd, dic, mapping):
  def upsingle(d,k,v):
    if k in mapping:
      d[mapping[k]] = v
    else:
      d[k] = v
  for ekey, evalue in dic.items():
    upsingle(newd, ekey, evalue)
    if type(evalue) is dict:
      update_keys(newd, evalue, mapping)
    if type(evalue) is list:
      upsingle(newd, ekey, [update_keys({}, i, mapping) for i in evalue])
  return newd

回答 20

我建议,以取代{}通过type(v)()以存储在任何字典子类的繁殖对象类型,u但不存在d。例如,这将保留诸如collections.OrderedDict之类的类型:

Python 2:

import collections

def update(d, u):
    for k, v in u.iteritems():
        if isinstance(v, collections.Mapping):
            d[k] = update(d.get(k, type(v)()), v)
        else:
            d[k] = v
    return d

Python 3:

import collections.abc

def update(d, u):
    for k, v in u.items():
        if isinstance(v, collections.abc.Mapping):
            d[k] = update(d.get(k, type(v)()), v)
        else:
            d[k] = v
    return d

I recommend to replace {} by type(v)() in order to propagate object type of any dict subclass stored in u but absent from d. For example, this would preserve types such as collections.OrderedDict:

Python 2:

import collections

def update(d, u):
    for k, v in u.iteritems():
        if isinstance(v, collections.Mapping):
            d[k] = update(d.get(k, type(v)()), v)
        else:
            d[k] = v
    return d

Python 3:

import collections.abc

def update(d, u):
    for k, v in u.items():
        if isinstance(v, collections.abc.Mapping):
            d[k] = update(d.get(k, type(v)()), v)
        else:
            d[k] = v
    return d

回答 21

这有点偏,但是您真的需要嵌套字典吗?根据问题的不同,有时平字典可能就足够了……并且看起来很不错:

>>> dict1 = {('level1','level2','levelA'): 0}
>>> dict1['level1','level2','levelB'] = 1
>>> update = {('level1','level2','levelB'): 10}
>>> dict1.update(update)
>>> print dict1
{('level1', 'level2', 'levelB'): 10, ('level1', 'level2', 'levelA'): 0}

That’s a bit to the side but do you really need nested dictionaries? Depending on the problem, sometimes flat dictionary may suffice… and look good at it:

>>> dict1 = {('level1','level2','levelA'): 0}
>>> dict1['level1','level2','levelB'] = 1
>>> update = {('level1','level2','levelB'): 10}
>>> dict1.update(update)
>>> print dict1
{('level1', 'level2', 'levelB'): 10, ('level1', 'level2', 'levelA'): 0}

回答 22

如果您想要单线:

{**dictionary1, **{'level1':{**dictionary1['level1'], **{'level2':{**dictionary1['level1']['level2'], **{'levelB':10}}}}}}

If you want a one-liner:

{**dictionary1, **{'level1':{**dictionary1['level1'], **{'level2':{**dictionary1['level1']['level2'], **{'levelB':10}}}}}}

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