如何更改Python字典中条目的键?
当前回答
我只是要帮我妻子做一些python类的事情,所以我写了这段代码来告诉她如何做。正如标题所示,它只替换键名。这是非常罕见的,你必须替换一个键名,并保持字典的顺序完整,但我还是想分享,因为这篇文章是当你搜索它时谷歌返回的,即使它是一个非常老的线程。
代码:
dictionary = {
"cat": "meow",
"dog": "woof",
"cow": "ding ding ding",
"goat": "beh"
}
def countKeys(dictionary):
num = 0
for key, value in dictionary.items():
num += 1
return num
def keyPosition(dictionary, search):
num = 0
for key, value in dictionary.items():
if key == search:
return num
num += 1
def replaceKey(dictionary, position, newKey):
num = 0
updatedDictionary = {}
for key, value in dictionary.items():
if num == position:
updatedDictionary.update({newKey: value})
else:
updatedDictionary.update({key: value})
num += 1
return updatedDictionary
for x in dictionary:
print("A", x, "goes", dictionary[x])
numKeys = countKeys(dictionary)
print("There are", numKeys, "animals in this list.\n")
print("Woops, that's not what a cow says...")
keyPos = keyPosition(dictionary, "cow")
print("Cow is in the", keyPos, "position, lets put a fox there instead...\n")
dictionary = replaceKey(dictionary, keyPos, "fox")
for x in dictionary:
print("A", x, "goes", dictionary[x])
输出:
A cat goes meow
A dog goes woof
A cow goes ding ding ding
A goat goes beh
There are 4 animals in this list.
Woops, that's not what a cow says...
Cow is in the 2 position, lets put a fox there instead...
A cat goes meow
A dog goes woof
A fox goes ding ding ding
A goat goes beh
其他回答
只需2步即可轻松完成:
dictionary[new_key] = dictionary[old_key]
del dictionary[old_key]
或者一步:
dictionary[new_key] = dictionary.pop(old_key)
如果字典[old_key]未定义,将引发KeyError。注意,这将删除字典[old_key]。
>>> dictionary = { 1: 'one', 2:'two', 3:'three' }
>>> dictionary['ONE'] = dictionary.pop(1)
>>> dictionary
{2: 'two', 3: 'three', 'ONE': 'one'}
>>> dictionary['ONE'] = dictionary.pop(1)
Traceback (most recent call last):
File "<input>", line 1, in <module>
KeyError: 1
方法,如果有人想替换多级字典中出现的所有键。
函数检查字典是否有特定的键,然后遍历子字典并递归调用该函数:
def update_keys(old_key,new_key,d):
if isinstance(d,dict):
if old_key in d:
d[new_key] = d[old_key]
del d[old_key]
for key in d:
updateKey(old_key,new_key,d[key])
update_keys('old','new',dictionary)
你可以使用iff/else字典理解。此方法允许您在一行中替换任意数量的键,并且不需要更改所有键。
key_map_dict = {'a':'apple','c':'cat'}
d = {'a':1,'b':2,'c':3}
d = {(key_map_dict[k] if k in key_map_dict else k):v for (k,v) in d.items() }
返回{“苹果”:1、“b”:2,“猫”:3}
d = {1:2,3:4}
假设我们想要改变列表元素p=['a', 'b']的键值。 下面的代码可以做到:
d=dict(zip(p,list(d.values())))
我们得到
{'a': 2, 'b': 4}
在python 2.7及更高版本中,您可以使用字典理解: 这是我在使用DictReader读取CSV时遇到的一个例子。用户已经在所有列名后面加上了':'
ori_dict ={“key1:”:1、“key2:”:2,“key3:”:3}
在键中去掉后面的':':
Corrected_dict = {k.replace(':', "): v for k, v in ori_dict.items()}
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