程序什么时候什么都没有提示

Question

我写了一个程序很匆忙，看看我是否可以改进一些我放弃的旧代码，因为我无法保存它，但现在我已经写入了一个。 csv文件它什么都不做。如果我在运行时尝试与它交互，即按1,2,3,4，则什么都不会发生，它甚至不会退出，原因是我无法排除故障。这里是代码，任何人都可以告诉我我失踪了什么？

import pandas as pd 
import csv 
import matplotlib.pyplot as plt 
import numpy as np 

myDict = {"Apples": 150, "Berries": 200, "Bananas": 300, "Oranges": 350} 

def menu(): 
    print("Press 1: To add stock. ") 
    print("Press 2: To check stock. ") 
    print("press 3: To enter purchase. ") 
    print("Press 4: To quit the program. ") 
    return input("What would you like to do? ") 

run = menu() 

while True: 
    if run == '1': 
     AddStock = input('Product to be added to stock? ') 
     Amount = int(input('Quantity of product to be added to stock? ')) 
     myDict[AddStock] = Amount 
     run = menu() 

    elif run == '2': 
     for key, value in myDict.items(): 
      print("{}: {}".format(key, value)) 
     run = menu() 

    elif run == '3': 
     product = input('What product was sold? ') 
     if product in myDict: 
       myDict[product] -= 1 
     else: 
      print("Product is out of stock! ") 
     run = menu() 

    elif run == '4': 
     with open('stock.csv', 'w') as stock: 
      writer = csv.writer(stock) 
      for key, value in myDict.items(): 
       writer.writerow([key, value]) 
       break 

Answer 1

既然没有人回答了这个问题......下面是一个快速解决问题的方法。虽然，我只会显示一次命令选项，而不是每次都显示。

import csv 

myDict = {"Apples": 150, "Berries": 200, "Bananas": 300, "Oranges": 350} 

def menu(): 
    print("Press 1: To add stock.") 
    print("Press 2: To check stock.") 
    print("press 3: To enter purchase.") 
    print("Press 4: To quit the program.") 
    return input("What would you like to do? ") 

run = None 
while run != '4': 
    run = menu() 
    if run == '1': 
     AddStock = input('Product to be added to stock? ') 
     Amount = int(input('Quantity of product to be added to stock? ')) 
     myDict[AddStock] = Amount 
    elif run == '2': 
     for key, value in myDict.items(): 
      print("{}: {}".format(key, value)) 

    elif run == '3': 
     product = input('What product was sold? ') 
     if product in myDict: 
      myDict[product] -= 1 
     else: 
      print("Product is out of stock! ") 

    elif run == '4': 
     with open('stock.csv', 'w', newline="") as stock: 
      writer = csv.writer(stock) 
      for key, value in myDict.items(): 
       writer.writerow([key, value])