Python映射对象不可下标

Question

为什么以下脚本会给出错误：

payIntList[i] = payIntList[i] + 1000 TypeError: 'map' object is not subscriptable

payList = []
numElements = 0

while True:
        payValue = raw_input("Enter the pay amount: ")
        numElements = numElements + 1
        payList.append(payValue)
        choice = raw_input("Do you wish to continue(y/n)?")
        if choice == 'n' or choice == 'N':
                         break

payIntList = map(int,payList)

for i in range(numElements):
         payIntList[i] = payIntList[i] + 1000
         print payIntList[i]

Answer 1

在Python 3中，map返回类型为的可迭代对象map，而不是可下标的列表，该列表允许您编写map[i]。要强制列出结果，请写

payIntList = list(map(int,payList))

但是，在许多情况下，您可以不使用索引来更好地编写代码。例如，使用列表推导：

payIntList = [pi + 1000 for pi in payList]
for pi in payIntList:
    print(pi)