在while循环中看不到Python嵌套的If Then语句答案

【问题标题】：Python Nested If Then statement not seen in while loop在while循环中看不到Python嵌套的If Then语句
【发布时间】：2019-12-11 15:03:13
【问题描述】：

我正在开发一个菜单应用程序 (CLI)，当用户从菜单中选择一个数字选项时，应用程序会为每个选项执行不同的操作。但首先我想确保他们输入一个有效的数字然后做一些事情。如果不是有效数字，则循环菜单。如果选择了数字 9，则退出应用程序。问题是它似乎无法识别我的嵌套 if then 条件语句。它只看到第一个 if then 条件，然后再次循环菜单而不“做某事”。如何让它识别嵌套的 if thens？

import datetime
import os
import pyfiglet

def main():
    Banner()
    menu()


def menu():
    choice =int('0')
    while choice !=int('9'):
        print("1. Show the banner again")
        print("2. View just a selected date range")
        print("3. Select a date range and show highest temperature")
        print("4. Select a date range and show lowest temperature")
        print("5. Select a data range and show the highest rainfall")
        print("6. Make a silly noise")
        print("7. See this menu again")
        print("9. QUIT the program")

        choice = input ("Please make a choice: ")

        if choice.isdigit():
          print(int(choice))
          if choice == 1:
            result = pyfiglet.figlet_format("P y t h o n  R o c k s", font = "3-d" )
            print(result)
          elif choice == 2:
            getWeather()
            choice == 0
          elif choice == 3:
            print("Do Something 3")
          elif choice == 4:
            print("Do Something 4")
          elif choice == 5:
            print("Do Something 5")
          elif choice == 6:
            os.system( "say burp burp burp burpeeeeee. I love love love this menu application")
          elif choice == 7:
            print("Do Something 7")
          elif choice == 8:
            print("Do Something 8")
          elif choice == 9:
            print("***********************************************************************")
            print("Goodbye! Program exiting.....")
            print("***********************************************************************")
            exit()
        else:
          print("Your choice is not an integer. Please try again")
          print("")
          continue

def Banner():
  result = pyfiglet.figlet_format("P y t h o n  R o c k s", font = "3-d" )
  print(result)

def getWeather():
  weatherdata1 = print(input("What date would you like to start your weather data query with? Please    enter the date in this format YYYYMMDD"))
  weatherdata2 = print(input("What date would you like to end your weather data query with? Please enter the date in this format YYYYMMDD"))
  print(weatherdata1)
  print(weatherdata2)


main()

【问题讨论】：

choice 是一个字符串，您将其与一个数字进行比较，因此它们永远不会是True，您实际上是在做"3" == 3。当您阅读输入 choice = int(input ("Please make a choice: ")) 时，您应该将选择转换为 int
谢谢，克里斯！有道理。

标签： python-3.x loops if-statement nested

【解决方案1】：

您必须将输入转换为int，如下所示：

choice = int(input ("Please make a choice: "))

或者，您需要在比较时将选项转换为int。像这样：

if int(choice) == 1:
    result = pyfiglet.figlet_format("P y t h o n  R o c k s", font = "3-d" )
    print(result)
elif int(choice) == 2:
    getWeather()
    choice == 0
...

【讨论】：

谢谢！有时，是一些简单的事情让我很不爽。