替代Goto，Python中的Label? [英] Alternative to Goto, Label in Python?

问题描述

我知道我无法使用Goto，而且我知道Goto并非答案.我读过类似的问题，但我只是想不出办法解决问题.

I know I can't use Goto and I know Goto is not the answer. I've read similar questions, but I just can't figure out a way to solve my problem.

所以，我正在编写一个程序，其中您必须猜一个数字.这是我遇到问题的一部分的摘录:

So, I'm writing a program, in which you have to guess a number. This is an extract of the part I have problems:

x = random.randint(0,100)    

#I want to put a label here

y = int(raw_input("Guess the number between 1 and 100: "))

if isinstance( y, int ):
    while y != x:
        if y > x:
            y = int(raw_input("Wrong! Try a LOWER number: "))
        else:
            y = int(raw_input("Wrong! Try a HIGHER number "))
else:
    print "Try using a integer number"
    #And Here I want to put a kind of "goto label"`

你会做什么?

推荐答案

有很多方法可以做到这一点，但是通常您会希望使用循环，并且您可能希望探索break和continue.这是一种可能的解决方案:

There are lots of ways to do this, but generally you'll want to use loops, and you may want to explore break and continue. Here's one possible solution:

import random

x = random.randint(1, 100)

prompt = "Guess the number between 1 and 100: "

while True:
    try:
        y = int(raw_input(prompt))
    except ValueError:
        print "Please enter an integer."
        continue

    if y > x:
        prompt = "Wrong! Try a LOWER number: "
    elif y < x:
        prompt = "Wrong! Try a HIGHER number: "
    else:
        print "Correct!"
        break

continue跳转到循环的下一个迭代，并且break完全终止循环.

continue jumps to the next iteration of the loop, and break terminates the loop altogether.

(还要注意，我将int(raw_input(...))包装在try/except中，以处理用户未输入整数的情况.在您的代码中，不输入整数只会导致异常.我将0更改为在randint调用中也设为1，因为根据您要打印的文本，您打算在1到100之间选择，而不是0到100.)

(Also note that I wrapped int(raw_input(...)) in a try/except to handle the case where the user didn't enter an integer. In your code, not entering an integer would just result in an exception. I changed the 0 to a 1 in the randint call too, since based on the text you're printing, you intended to pick between 1 and 100, not 0 and 100.)

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