再帰せずに、エントリを追加し、ネストされたディクショナリの特定のキーから値を取得、変更、または削除するにはどうすればよいですか？

私はPythonで行っているクールなプロジェクトに取り組んでおり、ループが通過できる回数（最大再帰深度）を制限することでサイズを制限するため、再帰なしでこれを行う方法が必要でした。この関数は、任意のサイズのネスト辞書で機能する必要があります。ネストされた辞書の特定のキーからエントリを追加したり、値を取得、変更、または削除したりするにはどうすればよいですか？SOでこれに対する適切な答えは見つかりませんでした。これらはすべて、過度に複雑であるか、再帰を使用しているためです。

まあ、あなたはまた別の方法に行くことができます：

d = {}
my_keystring = "fruits.orange.price"
d[my_keystring] = 5.75

print(F"Demo get value: {d[my_keystring]}\nThis is the PRICE of ORANGE in FRUITS.")

d[my_keystring] = 1.25
print(F"Demo set value: {d[my_keystring]}\nThis is the NEW PRICE of ORANGE in FRUITS!")

del d[my_keystring]
print(F"Demo del entry: fruits.orange.price is now {d.get(my_keystring)}!")

d['fruits.orange.in_stock'] = True
print(F"Demo add entry! Added a new entry called in_stock to fruits.orange, it's value is: {d['fruits.orange.in_stock']}")

どちらが得ます

Demo get value: 5.75
This is the PRICE of ORANGE in FRUITS.
Demo set value: 1.25
This is the NEW PRICE of ORANGE in FRUITS!
Demo del entry: fruits.orange.price is now None!
Demo add entry! Added a new entry called in_stock to fruits.orange, it's value is: True

これを正確に行うこの機能を示すこの単純なモジュールを作成しました。キーパス自体を知っている必要があります。あなたはデモを取り出してから、それをつかんで任意のプロジェクトで使用することができますGitHubの本がでライセンスされているとして、MITライセンス。楽しい！

これがベンチマークされるのを見るのは興味深いでしょう。

'''
MIT License

Copyright (c) 2019 Keith Cronin

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in 
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.'''

d = {}
d['fruits'] = {}
d['fruits']['orange'] = {}
d['fruits']['orange']['price'] = 5.75

my_keystring = "fruits.orange.price"

def get_value(keystring, dictionary):
    amountkeys = keystring.count('.')+1
    lastfoundindex = 0
    counter = 0

    while counter < amountkeys:
            if counter == 0:
                    value = dictionary[keystring[lastfoundindex:keystring.find('.')]]

            elif counter == amountkeys - 1:
                    value = value[keystring[lastfoundindex:]]
                    break
            else:
                    value = value[keystring[lastfoundindex:keystring.find('.',lastfoundindex)]]

            lastfoundindex = keystring.find('.',lastfoundindex)+1
            counter += 1

    return value

print(F"Demo get_value(): {get_value(my_keystring, d)}\nThis is the PRICE of ORANGE in FRUITS.")

def set_value(keystring, dictionary, new_value):
    amountkeys = keystring.count('.')+1
    lastfoundindex = 0
    counter = 0

    while counter < amountkeys:
            if counter == 0:
                    value = dictionary[keystring[lastfoundindex:keystring.find('.')]]

            elif counter == amountkeys - 1:
                    value[keystring[lastfoundindex:]] = new_value
                    break
            else:
                    value = value[keystring[lastfoundindex:keystring.find('.',lastfoundindex)]]

            lastfoundindex = keystring.find('.',lastfoundindex)+1
            counter += 1

    value = new_value
    return value

print(F"Demo set_value(): {set_value(my_keystring, d, 1.25)}\nThis is the NEW PRICE of ORANGE in FRUITS!")

def del_entry(keystring, dictionary):
    amountkeys = keystring.count('.')+1
    lastfoundindex = 0
    counter = 0

    while counter < amountkeys:
            if counter == 0:
                    value = dictionary[keystring[lastfoundindex:keystring.find('.')]]

            elif counter == amountkeys - 1:
                    del value[keystring[lastfoundindex:]]
                    break
            else:
                    value = value[keystring[lastfoundindex:keystring.find('.',lastfoundindex)]]

            lastfoundindex = keystring.find('.',lastfoundindex)+1
            counter += 1

del_entry('fruits.orange.price',d)
print(F"Demo del_entry(): fruits.orange.price is now {get_value('fruits.orange', d)}!")


def add_entry(keystring, dictionary, entry_name, entry_value = None):
    amountkeys = keystring.count('.')+1
    lastfoundindex = 0
    counter = 0

    while counter < amountkeys:
            if counter == 0:
                    value = dictionary[keystring[lastfoundindex:keystring.find('.')]]

            elif counter == amountkeys - 1:
                    value[keystring[lastfoundindex:]][entry_name] = entry_value
                    break
            else:
                    value = value[keystring[lastfoundindex:keystring.find('.',lastfoundindex)]]

            lastfoundindex = keystring.find('.',lastfoundindex)+1
            counter += 1

add_entry('fruits.orange', d, 'in_stock', True)
print(F"Demo add_entry()! Added a new entry called in_stock to fruits.orange, it's value is: {get_value('fruits.orange.in_stock',d)}")