python - 在 randint 参数中使用变量

Question

这里完全是初学者，

我正在编写一个为用户掷骰子的程序，我希望它能够更改每个用户输入的骰子面数。我似乎无法让变量 amount_faces 作为 randint() 函数的 int 工作，每次都会收到“TypeError:无法连接 'str' 和 'int' 对象”错误:

from sys import exit
from random import randint

def start():
    print "Would you like to roll a dice?"
    choice = raw_input(">")
    if "yes" in choice:
        roll()
    elif "no" in choice:
        exit()
    else:
        print "I can't understand that, try again."
        start()

def roll():
    print "How many faces does the die have?"
    amount_faces = raw_input(">")
    if amount_faces is int:
        print "The number of faces has to be an integer, try again."
        roll()
    else:            
        print "Rolling die...."
        int(amount_faces)
        face = randint(1,*amount_faces)
        print "You have rolled %s" % face
        exit()

start()

有什么线索吗？

Answer 1

int(amount_faces) 不会就地更改 amount_faces。您需要分配函数返回的整数对象:

amount_faces = int(amount_faces)

amount_faces 不是可迭代的，因此您不能在此处使用 *arg 语法:

face = randint(1,*amount_faces)

您必须删除*:

face = randint(1, amount_faces)

您也没有在这里正确测试整数:

if amount_faces is int:

int 是一个类型对象，amount_faces 只是一个字符串。您可以捕获 int() 抛出的 ValueError 来检测输入不可转换，而是:

while True:
    amount_faces = raw_input(">")
    try:
        amount_faces = int(amount_faces)
    except ValueError:
        print "The number of faces has to be an integer, try again."
    else:
        break

print "Rolling die...."
face = randint(1, amount_faces)
print "You have rolled %s" % face

您可能想查看 Asking the user for input until they give a valid response并且不使用递归进行程序控制。