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问题描述

我有一个值错误,即使我尝试玩代码,它不起作用。



我如何得到正确的? - 我使用的是Python 3.3.2!



这里是代码:



如您所见,程序会询问您可以走几英里,并根据您输入的内容给出回应。 p>

这是文本格式的代码:

  print(欢迎来到
miles = input(你可以走几英里?)
如果float(英里)< = 0:
print(你以为你是谁?!!现在就走1000英里!)
elif float(miles)> = 10:
print(你很健康!保持起来!
elif float(miles)> 0和里程<
print(Good,Try doing 10 miles)
else:
print(请输入一个数字!)
miles = float(input你可以走几英里?))
如果里程< = 0:
print(你认为你是谁?现在去走1000英里!)
elif miles> = 10:
print(你很健康!保持起来!)
elif miles> 0和里程< 10:
打印(好,尝试做10英里)


解决方案

这个问题正是Traceback日志所说的:无法将字符串转换为float




  • 如果您只有一个字符串,只有数字,python足够聪明地做你想要的,并将字符串转换为一个浮动。

  • 如果你有一个字符串使用非数字字符,转换将失败,并提供您所遇到的错误。



大多数人会接近的方式问题是使用 try / except (请参阅),或使用 isdigit()函数(请参阅)。



尝试/除外

  try:
miles = float(input(你可以走几英里?))
ex cept:
print(请输入一个数字!)

Isdigit ()

  miles = input(你可以走几英里?)
if不是miles.isdigit():
print(请输入一个数字!)

请注意,如果字符串中有小数点,则后者仍将返回false



编辑



好吧,我将无法再回到你一段时间,所以我会发布答案,以防万一。

  while真的:
try:
miles = float(input(你可以走几英里?))
break
除了:
print(请输入一个数字!)

#所有的ifs和东西

代码很简单:




  • 它将继续尝试将输入转换为浮点数,如果失败,循环回到开始。 li>
  • 最终成功后,会破坏f循环并转到你放下的代码。


I got a value error and even if I try playing around with the code, it doesn't work!

How can I get it right? - I am using Python 3.3.2!

Here is the code:

As you can see, the program asks for how many miles you can walk and gives you a response depending on what you type in.

This is the code in text format:

print("Welcome to Healthometer, powered by Python...")
miles = input("How many miles can you walk?: ")
if float(miles) <= 0:
    print("Who do you think you are?!! Go and walk 1000 miles now!")
elif float(miles) >= 10:
    print("You are very healthy! Keep it up!")
elif float(miles) > 0 and miles < 10:
    print("Good. Try doing 10 miles")
else:
    print("Please type in a number!")
    miles = float(input("How many miles can you walk?: "))
    if miles <= 0:
        print("Who do you think you are?!! Go and walk 1000 miles now!")
    elif miles >= 10:
        print("You are very healthy! Keep it up!")
    elif miles > 0 and miles < 10:
        print("Good. Try doing 10 miles")
解决方案

The problem is exactly what the Traceback log says: Could not convert string to float

  • If you have a string with only numbers, python's smart enough to do what you're trying and converts the string to a float.
  • If you have a string with non-numerical characters, the conversion will fail and give you the error that you were having.

The way most people would approach this problem is with a try/except (see here), or using the isdigit() function (see here).

Try/Except

try:
    miles = float(input("How many miles can you walk?: "))
except:
    print("Please type in a number!")

Isdigit()

miles = input("How many miles can you walk?: ")
if not miles.isdigit():
    print("Please type a number!")

Note that the latter will still return false if there are decimal points in the string

EDIT

Okay, I won't be able to get back to you for a while, so I'll post the answer just in case.

while True:
    try:
        miles = float(input("How many miles can you walk?: "))
        break
    except:
        print("Please type in a number!")

#All of the ifs and stuff

The code's really simple:

  • It will keep trying to convert the input to a float, looping back to the beginning if it fails.
  • When eventually it succeeds, it'll break from the loop and go to the code you put lower down.

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08-24 08:56