如果列表中没有'milk'，为什么我的代码不会在列表末尾添加'milk'？]

Question

shopping_cart = [['tooth paste', 'q-tips', 'milk],['milk', 'candy', 'apples'],['planner', 'pencils', 'q-tips']]

for x in shopping_cart: #this is the overall list
    for i in shopping_cart: #This is the 3 inner lists?
        if shopping_cart[0:2] != 'milk': # this should check for milk in list
            shopping_cart.append('milk') # this should append milk to the end of the list if milk isnt in yet

shopping_cart = [['牙膏'，'q-tips，'牛奶'，''milk'，'candy'，'apples]，['planner'，'铅笔'，'q-tips]] ] for shopping_cart中的x：＃这是shopping_cart中i的整体列表：＃这是...

Answer 1

由于您没有提到预期的输出，我假设这就是您要寻找的。