使用python中的动态键和值更新字典
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update dictionary with dynamic keys and values in python
提问by user850287
I have a dictionary and I want to insert keys and values dynamically but I didn't manage to do it. The problem is that when I use the update method it doesn't add a pair but it deletes the previous values so I have only the last value when printing the dictionary here is my code
我有一本字典，我想动态插入键和值，但我没能做到。问题是，当我使用 update 方法时，它不会添加一对，但会删除以前的值，因此在打印字典时我只有最后一个值，这里是我的代码
i = 0
for o in iterload(f):
i=i+1
mydic = {i : o["name"]}
mydic.update({i : o["name"]})
for k, v in mydic.items():
print(k,v)
print(mydic)
f is a file that i'm parsing with python code as a result I get
f 是我用 python 代码解析的文件，结果我得到
{3: 'toto'}
which is the last element. is there a solution to have all the elements in my dictionary
这是最后一个元素。有没有办法在我的字典中包含所有元素
Thanks in advance
提前致谢
I have another question
我有另一个问题
Now I need to chek if an input value equals a key from my dictionary and if so I need to get the value of this key to continue parsing the file and get other informations.
现在我需要检查输入值是否等于我字典中的键，如果是，我需要获取此键的值以继续解析文件并获取其他信息。
Here is my code :
这是我的代码：
f = open('myfile','r')
nb_name = input("\nChoose the number of the name :")
for o in iterload(f):
if o["name"] == mydic[nb_name]:
...
I get a keyError
我收到一个 keyError
Traceback (most recent call last):
File ".../test.py", line 37, in <module>
if o["name"] == mydic[nb_name]:
KeyError: '1'
I don't understand the problem
我不明白这个问题
采纳答案by NPE
Remove the following line:
删除以下行：
mydic = {i : o["name"]}
and add the following before your loop:
并在循环之前添加以下内容：
mydic = {}
Otherwise you're creating a brand new one-element dictionary on every iteration.
否则，您将在每次迭代中创建一个全新的单元素字典。
Also, the following:
此外，以下内容：
mydic.update({i : o["name"]})
is more concisely written as
更简洁地写为
mydic[i] = o["name"]
Finally, note that the entire loop can be rewritten as a dictionary comprehension:
最后，请注意，整个循环可以重写为字典推导式：
mydic = {i+1:o["name"] for i,o in enumerate(iterload(f))}
回答by jfs
@NPE pointed out the problemin your code (redefining the dict on each iteration).
@NPE 指出了您代码中的问题（在每次迭代时重新定义 dict）。
Here's one more way to generate the dict (Python 3 code):
这是生成字典的另一种方法（Python 3 代码）：
from operator import itemgetter
mydict = dict(enumerate(map(itemgetter("name"), iterload(f)), start=1))
About the KeyError: '1': input()returns a string in Python 3 but the dictionary mydictexpects an integer. To convert the string to integer, call int:
关于KeyError: '1':input()在 Python 3 中返回一个字符串，但字典mydict需要一个整数。要将字符串转换为整数，请调用int：
nb_name = int(input("\nChoose the number of the name :"))
回答by HelpNeeder
You could use len()to insert the value:
您可以使用len()插入值：
#!/usr/bin/python
queue = {}
queue[len(queue)] = {'name_first': 'Jon', 'name_last': 'Doe'}
queue[len(queue)] = {'name_first': 'Jane', 'name_last': 'Doe'}
queue[len(queue)] = {'name_first': 'J', 'name_last': 'Doe'}
print queue
