Python中if语句未执行：简易计算器代码故障排查

你的代码存在三个核心问题，导致分支无法触发或后续运算报错：

1. 功能选择的类型不匹配 #

userInput是input()返回的字符串，后续用userInput == 1这类整数比较永远不会成立，自然无法进入分支。需要在验证通过后，将userInput转为整数并赋值：

# 原代码此处为无效的str(userInput)，替换为：
userInput = int(userInput)
break

2. 数值输入未实际转换类型 #

输入variableA和variableB时，float(variableA)仅执行了转换操作，但未将结果存回变量，导致变量仍为字符串类型，传给运算函数会触发错误。修改为：

# 原代码此处为float(variableA)，替换为：
variableA = float(variableA)
break

variableB做同样修改即可。

3. 第6分支的逻辑错误 #

你误用sub函数判断数值大小，应该调用自己定义的gt函数；且原逻辑中sub返回数值，和True/False比较完全不成立。修正第6分支代码：

elif userInput == 6:
    print("Is the first input greater than the second?")
    result = gt(variableA, variableB)
    if result == "Equal":
        print(f"It is {result}. Both numbers are the same.")
    elif result:
        print(f"{result}. {variableA} is greater than {variableB}")
    else:
        print(f"{result}. {variableB} is greater than {variableA}")
    print("Thank you")

修改后的完整代码 #

import operator as op
print("Greetings user, welcome to the calculator program.\nWe offer a list of functions:")
print("1. Add\n2. Subtract\n3. Multiply\n4. Divide\n5. Modulus\n6. Check greater number")
while True:
    userInput = input("Please choose what function you would like to use based on their numbers:")
    if userInput.isdigit():
        if int(userInput) in range(1,7):
            userInput = int(userInput)
            break
        else:
            print("Number inputted is either below or above the given choices")
            continue
    else:
        print("Incorrect input. Please try again.")
        continue

def add(x,y):
    return op.add(x,y)

def sub(x,y):
    return op.sub(x,y)

def mul(x,y):
    return op.mul(x,y)

def div(x,y):
    return op.truediv(x,y)

def mod(x,y):
    return op.mod(x,y)

def gt(x,y):
    if x == y:
        return "Equal"
    else:
        return op.gt(x,y)

variableA = 0
variableB = 0

while True:
    variableA = input("Enter the first value: ")
    if variableA.isdigit():
        variableA = float(variableA)
        break
    else:
        print("Incorrect input. Please try again.")
        continue

while True:
    variableB = input("Enter the second value: ")
    if variableB.isdigit():
        variableB = float(variableB)
        break
    else:
        print("Incorrect input. Please try again.")
        continue
    
if userInput == 1:
    print("You chose to add the two numbers and the result is:")
    print(add(variableA,variableB))
    print("Thank you")
elif userInput == 2:
    print("You chose to subtract with the two numbers and the result is:")
    print(sub(variableA,variableB))
    print("Thank you")
elif userInput == 3:
    print("You chose to multiply the two numbers and the result is:")
    print(mul(variableA,variableB))
    print("Thank you")
elif userInput == 4:
    print("You chose to divide with the two numbers and the result is:")
    print(div(variableA,variableB))
    print("Thank you")
elif userInput == 5:
    print("You chose to find the modulo with the two numbers and the result is:")
    print(mod(variableA,variableB))
    print("Thank you")
elif userInput == 6:
    print("Is the first input greater than the second?")
    result = gt(variableA, variableB)
    if result == "Equal":
        print(f"It is {result}. Both numbers are the same.")
    elif result:
        print(f"{result}. {variableA} is greater than {variableB}")
    else:
        print(f"{result}. {variableB} is greater than {variableA}")
    print("Thank you")

内容的提问来源于stack exchange，提问作者Depleted Money