如何正确地加上括号，以免不必要地使用括号python3

Question

我正在制作一个将Prefix转换为Infix的程序，但在将括号放在表达式时遇到了问题。为了进行转换，我使用经典的堆栈算法。这是我的简单功能。

def breckets(operand1, operand2, operace):
    res = ""
    if (operand1.isdigit()) and (operand2.isdigit()):
        res = operand1 + operace + operand2
    elif (operand1.isdigit()) and (not operand2.isdigit()):
        if operace == "+":
            res = operand1 + operace + operand2
        else:
            res = operand1 + operace + "(" + operand2 + ")"
    elif (not operand1.isdigit()) and (operand2.isdigit()):
        if prior(operace) != 0:
            res = "(" + operand1 + ")" + operace + operand2
        else:
            res = operand1 + operace + operand2
    else:
        res = "(" + operand1 + ")" + operace + "(" + operand2 + ")"
    return res

def prior(a):
    prior = None
    if a in "+-":
        prior = 0
    elif a in "*/":
        prior = 1
    elif a in "^":
        prior = 2
    else:
        print("Something went wrong")
        exit()
    return prior

但是我一定不要不必要地使用括号，任何人都可以给我一些建议吗？

Answer 1

这应该做：

def breckets(operand1, operand2, operace):
    res = ""
    if operand1.isdigit() and operand2.isdigit():
        res = operand1 + operace + operand2
    elif operand1.isdigit() and not operand2.isdigit():
        if operace == "+":
            res = operand1 + operace + operand2
        else:
            res = f"{operand1} {operace} ({operand2})"
    elif not operand1.isdigit() and operand2.isdigit():
        if prior(operace) != 0:
            res = f"({operand1}) {operace} {operand2}"
        else:
            res = operand1 + operace + operand2
    else:
        res = f"{operand1}){operace}({operand2})"
    return res

    def prior(a):
    prior = None
    if a in "+-":
        prior = 0
    elif a in "*/":
        prior = 1
    elif a in "^":
        prior = 2
    else:
        print("Something went wrong")
        exit()
    return prior