Dict KeyError获取字典中的值 [英] Dict KeyError for value in the dict
问题描述
我在字典中有一个字典:
I have a dict inside a dict:
{
'123456789': {u'PhoneOwner': u'Bob', 'Frequency': 0},
'98765431': {u'PhoneOwner': u'Sarah', 'Frequency': 0},
}
这个想法是扫描由号码组成的通话清单,并与dict进行比较,从而增加每次找到匹配项的频率.
The idea is to scan a list of calls made by numbers and compare against the dict, increasing the frequency each time a match is found.
当我运行脚本时:
try:
phoneNumberDictionary[int(line)]['Frequency'] += 1
except KeyError:
phoneNumberDictionary[int(line)]['Frequency'] = 1
我收到错误消息:
KeyError: '18667209918'
(其中18667209918是当前正在搜索的号码)
(Where 18667209918 is the number that is currently being searched)
但是,当我打印字典并仅搜索该数字时,便可以立即找到它. 有什么想法吗?
Yet when I print the dict and just search for that number I can find it immediately. Any ideas?
推荐答案
dictionary = {
'123456789': {u'PhoneOwner': u'Bob', 'Frequency': 0},
'98765431': {u'PhoneOwner': u'Sarah', 'Frequency': 0},
}
key_present = '123456789'
try:
dictionary[key_present]['Frequency'] += 1
except KeyError:
pass
key_not_present = '12345'
try:
dictionary[key_not_present]['Frequency'] += 1
except KeyError:
dictionary[key_not_present] = {'Frequency': 1}
print dictionary
您将字符串作为字典中的键,但要使用整数键进行访问.
you have strings as keys in the dictionary but to access you are using an integer key.
我认为您仍将从异常块中的语句中获得KeyError
.从您的语句phoneNumberDictionary[int(line)]['Frequency'] = 1
中,python假定您通过的键存在一个键值,并且它具有一个dictionary
(其中Frequency
作为其键之一).但是首先您有KeyError
异常,因为您没有与18667209918
I think you will still get KeyError
from the statement in the exception block. from your statement phoneNumberDictionary[int(line)]['Frequency'] = 1
python assumes that a key-value exists with the key you have passes and it has a dictionary
with Frequency
as one of its key. But you have got KeyError
exception in the first place because you did not have a key matching 18667209918
因此,正确初始化外部字典的键值对.
Therefore initialize the key-value pair of the outer dictionary properly.
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