python中的while循环不起作用

Question

pointsToAdd = 30
strengthPoints = 0
healthPoints = 0
wisdomPoints= 0
dexterityPoints = 0

while pointsToAdd > 0:
    choice = int(input("Choice(1-4): "))
    if choice == 1:
        pointsToAdd = int(input("How many Strength points would you like to add: "))
        if pointsToAdd < 31 and pointsToAdd > 0 and pointsToAdd - strengthPoints > 0:
            strengthPoints += pointsToAdd
            pointsToAdd -= strengthPoints
            print("You now have",strengthPoints,"strength points")
        elif pointsToAdd > 30:
            print("You cannot add that many!")
        elif pointsToAdd<1:
            print("You cannot add less than one point!")
        elif pointsToAdd - strengthPoints <= 0:
            print("You only have",pointsToAdd,"points!")
        else:
            print("We are sorry, but an error has occurred")

我试图做到这一点，以便用户可以输入四个类别中任何一个类别的积分，但是最多可以使用30积分（我尚未编写有关健康，智慧或敏捷积分的代码）。 为什么当我运行程序时，如果您选择在1-30之间添加多个点，则循环只会再次运行？ 如果用户使用不在1到30之间的数字输入要分配给strengthPoints的点，则循环将运行关联的if语句，但不会再次循环运行，为什么会这样呢？

Answer 1

您将相同的变量用于两个不同的目的pointsToAdd 。 您可以将其作为要分配的总分，以及用户选择要添加到统计中的内容。 一旦用用户的选择踩了总分，就将其加到0强度，然后从用户输入的值中减去它，将其设置为零。 使用如下所示的变量来修复它。

totalPointsToAdd = 30
strengthPoints = 0
healthPoints = 0
wisdomPoints= 0
dexterityPoints = 0

while totalPointsToAdd > 0:
    choice = int(input("Choice(1-4): "))
    if choice == 1:
        pointsToAdd = int(input("How many Strength points would you like to add: "))
    if pointsToAdd < 31 and pointsToAdd > 0 and pointsToAdd - strengthPoints > 0:
        strengthPoints += pointsToAdd
        totalPointsToAdd -= pointsToAdd
        print("You now have",strengthPoints,"strength points")

Answer 2

你做

pointsToAdd = 30

然后在循环中

pointsToAdd = int(input("How many Strength points would you like to add: "))

然后在测试

# Here pointsToAdd is not 30, but the value inputed by the user
strengthPoints += pointsToAdd
# Here strengthPoints == pointsToAdd == the value from the input
pointsToAdd -= strengthPoints
# Here pointsToAdd == 0

导致比之后的pointsToAdd == 0 。

您需要使用另一个变量来输入用户。

Answer 3

正如其他指出的那样，您正在覆盖相同的变量pointsToAdd 。 我还认为您可以将条件减少到两个：

pointsToAdd = 30
strengthPoints = 0

while pointsToAdd:
    print ('You have', pointsToAdd, 'available points.')
    choice = int(input("Choice(1-4): "))
    if choice == 1:
        toBeAdded = int(input("How many Strength points would you like to add: "))
        if toBeAdded < 1: # Can't assign negative or null values
            print("You cannot add less than one point!")
            continue
        if toBeAdded > pointsToAdd: # Don't have enough points to spend
            print("You only have", pointsToAdd, "available points!")
            continue
        strengthPoints += toBeAdded
        pointsToAdd -= toBeAdded
        print("You now have", strengthPoints, "strength points")

Answer 4

在Python 2.x中使用：raw_input在Python 3.x中使用：输入

如果要在Python 2.x和3.x之间兼容，可以使用：

try:
    input = raw_input
except NameError:
    pass