处理字典中的键错误的最佳方法 [英] Best way to handle a keyerror in a dict

问题描述

当我尝试从字典中获取值时，我想知道处理键盘错误的最佳方法.

I would like to know the best way to handle a keyerror, when I try to get a value from a dict.

我需要这个，因为我的字典包含一些事件的计数.每当发生事件时，我都会从dict中获取计数并对其进行递增并放回原处.

I need this because my dict holds the counts of some events. And whenever an event occurs I take the count from the dict and increment it and put it back.

我在网上找到了一些解决方案，但是它们是针对其他一些语言的.感谢您的帮助.

I found some solutions online, but they were for some other languages. Any help is appreciated.

我现在正在处理keyerror异常.想知道最好的方法来处理字典中的键盘错误.

I am handling the keyerror exception now. Would like to know the best approach to handle a keyerror in a dictionary.

注意:这不是要对列表中的项目进行计数，而是要从dict检索值(不存在)时处理异常.

Note: This is not about counting items in a list but about handling exception when retrieving a value(that does not exist) from a dict.

推荐答案

如果要使用dict

mydict[key] = mydict.get(key, 0) + 1

或者您可以处理KeyError

try:
    mydict[key] += 1
except KeyError:
    mydict[key] = 1

或者您可以使用defaultdict

from collections import defaultdict
mydict = defaultdict(int)
mydict[key] += 1

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