Question

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我正在编程一个程序，告诉你你是否已经足够投票了。并且，当它询问您的年龄时，如果用户键入字母而不是数字，我希望它说出某些内容，例如＆＃34;请输入数字，而不是字母。重新启动＆＃34。这是我现在的代码：

name = raw_input("What is your name?: ")
print("")
print("Hello, "+name+".\n")
print("Today we will tell you if you are old enough to vote.")
age = input("How old are you?: ")
if age >= 18:
    print("You are old enough to vote, "+name+".")
elif age < 18:
    print("Sorry, but you are not old enough to vote, "+name+".")

Answer 1

name = raw_input("What is your name?: ")
print("")
print("Hello, "+name+".\n")
print("Today we will tell you if you are old enough to vote.")
while True:
    age = raw_input("How old are you?: ")
    try:
        age = int(age)
    except ValueError:
        print("Please enter a number, not a letter. Restart.")
    else:
        break
if age >= 18:  
    print("You are old enough to vote, "+name+".")
elif age < 18:    # else:
    print("Sorry, but you are not old enough to vote, "+name+".")

在try-except-else中，我们尝试将年龄从字符串转换为整数。如果发生ValueError，则表示输入字符串不是合法整数。如果没有，那么我们可以简单地跳出while循环并执行以下任务。

注1：最好不要在python2中使用input()。请参阅this。

注2：elif没用。只需使用else。

Answer 2

您可以尝试这样的事情：

name = raw_input("What is your name?: ")
print("")
print("Hello, "+name+".\n")
print("Today we will tell you if you are old enough to vote.")
while True:
    try:
        #get the input to be an integer.
        age = int(raw_input("How old are you?: "))
        #if it is you break out of the while
        break
    except ValueError:
        print("Please enter a number, not a letter. Restart.")
if age >= 18:
    print("You are old enough to vote, "+name+".")
elif age < 18:
    print("Sorry, but you are not old enough to vote, "+name+".")

检测输入是int还是str•Python 2.7

2 个答案: