来自用户输入的python中的无限循环

Question

I am writing Python code counting up to the number the user provides, but I get into an infinite loop when running the code. Please note I tried commenting out lines 3 and 4 and replaced "userChoice" with a number, let's say for example 5, and it works fine.

import time

print "So what number do you want me to count up to?"
userChoice = raw_input("> ")

i = 0
numbers = []

while i < userChoice:
    print "At the top i is %d" % i
    numbers.append(i)

    i = i + 1
    print "Numbers now: ", numbers
    print "At the bottom i is %d" % i
    time.sleep(1)

print "The numbers: "

for num in numbers:
    print num
    time.sleep(1)

Answer 1

raw_input returns a string, not int . You can fix the issue by converting user response to int :

userChoice = int(raw_input("> "))

In Python 2.x objects of different types are compared by the type name so that explains the original behavior since 'int' < 'string' :

CPython implementation detail: Objects of different types except numbers are ordered by their type names; objects of the same types that don't support proper comparison are ordered by their address.

Answer 2

You are comparing a number with a string in:

while i < userChoice:

The string will always be greater than the number. At least in Python 2 where these are comparable.

You need to turn userChoice into a number:

userChoice = int(raw_input("> "))