Question

我正在使用python 3并且需要在函数内打印最终结果（这不是可选的）。相反，它每次通过功能时都会打印。

def reverseDisplay(number):
#base case 
#if number is only one digit, return number

  if number<10:
        return number 
  else:
        result = int(str(number%10) + str(reverseDisplay(number//10)))


  print(result)
  return(result)

def main():
     number = int(input("Enter a number: "))
     reverseDisplay(number)

main()

如果您输入12345，则会打印出

我希望它打印出54321

Answer 1

您只需将print声明移出reverseDisplay并转入main：

def reverseDisplay(number):
#base case 
#if number is only one digit, return number

  if number<10:
        return number 
  else:
        result = int(str(number%10) + str(reverseDisplay(number//10)))
  return result

def main():
    number = 12345
    print reverseDisplay(number)

main()

Answer 2

如果你真的需要在递归函数中打印它，你必须添加一个参数（在这个例子中称为first），以确保你只在第一次打印：

def reverseDisplay(number, first=True):
    if number<10:
        return number 
    else:
        result = int(str(number%10) + str(reverseDisplay(number//10, False)))
        if first:
            print(result)
        return result

Answer 3

以下对我有用（在我发现在线Python 3翻译后）：

def reverseDisplay(n):
    tmp = n % 10       # Determine the rightmost digit,
    print(tmp, end="") #  and print it with no space or newline.
    if n == tmp:       # If the current n and the rightmost digit are the same...
        print()        #    we can finally print the newline and stop recursing.
    else:              # Otherwise...
        reverseDisplay(n // 10)  # lop off the rightmost digit and recurse.

如果除了打印之外还需要返回反转值：

def reverseDisplay(n):
    tmp = n % 10
    print(tmp, end="")
    if n == tmp:
        print()
        return tmp
    else:
        return int(str(tmp) + str(reverseDisplay(n // 10)))

Answer 4

试试这个：

def reverseDisplayPrinter(number):
    print reverseDisplay(number)

def reverseDisplay(number):
    if number<10:
        return number 
    else:
        result = int(str(number%10) + str(reverseDisplay(number//10)))

    return(result)

def main():
    number = int(input("Enter a number: "))
    reverseDisplayPrinter(number)

main()

我正在使用递归函数，需要在函数内打印一次

4 个答案: