Python 检查输入是否为正整数
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Check if input is positive integer
提问by shivampaw
I need to check whether what the user entered is positive. If it is not I need to print an error in the form of a msgbox.
我需要检查用户输入的内容是否是肯定的。如果不是，我需要以 msgbox 的形式打印错误。
number = input("Enter a number: ")
###################################
try:
val = int(number)
except ValueError:
print("That's not an int!")
The above code doesn't seem to be working.
上面的代码似乎不起作用。
Any ideas?
有任何想法吗？
回答by Padraic Cunningham
while True:
number = input("Enter a number: ")
try:
val = int(number)
if val < 0: # if not a positive int print message and ask for input again
print("Sorry, input must be a positive integer, try again")
continue
break
except ValueError:
print("That's not an int!")
# else all is good, val is >= 0 and an integer
print(val)
回答by W1ll1amvl
what you need is something like this:
你需要的是这样的：
goodinput = False
while not goodinput:
try:
number = int(input('Enter a number: '))
if number > 0:
goodinput = True
print("that's a good number. Well done!")
else:
print("that's not a positive number. Try again: ")
except ValueError:
print("that's not an integer. Try again: ")
a while loop so code continues repeating until valid answer is given, and tests for the right input inside it.
一个while循环，因此代码继续重复直到给出有效答案，并测试其中的正确输入。
