以下是我的Python代码:
from collections import defaultdict
data = {"Manoj":{"India":{"Airtel":2000,"Vodafone":5000},"Pakistan":{"Airtel":3000}},
"Shafiq":{"Pakistan":{"Airtel":5000,"BP":10000}},
"Shams":{"India":{"BP":400}},
"Govind":{"India":{"Airtel":3000,"Vodafone":2000}},
"Zakir":{"SriLanka":{"Etisalat":7000}}
}
print("Printing data:")
print(data)
sumOperator={}
countryCustomers = defaultdict(list)
sum=0
for name,value in data.items():
for country,value2 in value.items():
countryCustomers[country].append(name)
if country not in sumOperator:
sumOperator[country]=value2
else:
for operator,value3 in value2.items():
if operator not in sumOperator[country]:
sumOperator[country][operator] = value3
else:
sum = sumOperator[country][operator] + value3
sumOperator[country][operator] = sum
print("")
print("Printing sumOperator:")
print(sumOperator)
print("")
print("Priniting data:")
print(data)
Output:
Printing data:
{'Zakir': {'SriLanka': {'Etisalat': 7000}}, 'Manoj': {'Pakistan': {'Airtel':3000}, 'India': {'Vodafone': 5000, 'Airtel': 2000}}, 'Shams': {'India': {'BP': 400}}, 'Shafiq': {'Pakistan': {'BP': 10000, 'Airtel': 5000}}, 'Govind': {'India': {'Vodafone': 2000, 'Airtel': 3000}}}
Printing sumOperator:
{'Pakistan': {'BP': 10000, 'Airtel': 8000}, 'SriLanka': {'Etisalat': 7000}, 'India': {'Vodafone': 7000, 'BP': 400, 'Airtel': 5000}}
Priniting data:
{'Zakir': {'SriLanka': {'Etisalat': 7000}}, 'Manoj': {'Pakistan': {'BP': 10000, 'Airtel': 8000}, 'India': {'Vodafone': 7000, 'BP': 400, 'Airtel': 5000}}, 'Shams': {'India': {'BP': 400}}, 'Shafiq': {'Pakistan': {'BP': 10000, 'Airtel': 5000}}, 'Govind': {'India': {'Vodafone': 2000, 'Airtel': 3000}}}
为什么我的字典“数据”在初始化另一个字典后会改变值?最后一个打印数据语句生成另一个数据字典,它与一开始初始化的数据字典不同
最佳答案
当您的程序将值添加到 sumOperator 字典时,并且主要是在循环中的最后一个 else
语句中,就会出现问题。您正在尝试根据另一个字典的值构建此字典,因此您有 sumOperator[key] = value
,其中 value
引用另一个字典中的项目。这只是将一个字典指向另一个字典的值;不复制基础值。因此,当您更新 sumOperator 的值时,主 data 字典也会更新。要解决此问题,只需在将值添加到新字典时复制它们即可。
以下代码有效,我们只需在更新 sumOperator 时添加 copy()
即可:
from collections import defaultdict
from copy import copy
data = {"Manoj":{"India":{"Airtel":2000,"Vodafone":5000},"Pakistan":{"Airtel":3000}},
"Shafiq":{"Pakistan":{"Airtel":5000,"BP":10000}},
"Shams":{"India":{"BP":400}},
"Govind":{"India":{"Airtel":3000,"Vodafone":2000}},
"Zakir":{"SriLanka":{"Etisalat":7000}}
}
print("Printing data:")
print(data)
sumOperator={}
countryCustomers = defaultdict(list)
sum=0
for name,value in data.items():
for country,value2 in value.items():
countryCustomers[country].append(name)
if country not in sumOperator:
sumOperator[country] = copy(value2)
else:
for operator,value3 in value2.items():
if operator not in sumOperator[country]:
sumOperator[country][operator] = copy(value3)
else:
sum = sumOperator[country][operator] + copy(value3)
sumOperator[country][operator] = sum
print("Printing sumOperator:")
print(sumOperator)
print("Priniting data:")
print(data)
正如其他人所指出的,您可能希望查看 assignment statements and copying 上的 Python 文档页面。 。如果您不想修改原始版本,请务必记住何时需要创建显式副本。
关于python - 为什么我的字典值在循环后发生变化?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29329910/