l = list()

l = []

fruits = ['apple', 'banana', 'pear', 'grapes', 'pineapple', 'watermelon']
fruits[2] #从0开始数起，第三个元素
pear

fruits[2] = 'tomato'
print(fruits)
['apple', 'banana', 'tomato', 'grapes', 'pineapple', 'watermelon']

fruits.append('eggplant')
print(fruits)
['apple', 'banana', 'tomato', 'grapes', 'pineapple', 'watermelon', 'eggplant']

print(fruit[: 2]) #从list的首元素开始截取，截取到位置'3'，但不包括第3个元素
['apple', 'banana']

fruits[:2] = ['a', 'b']
print(fruits)
['a', 'b', 'tomato', 'grapes', 'pineapple', 'watermelon', 'eggplant']

fruits[:2] = [] #删除前两个元素
print(fruits)
['tomato', 'grapes', 'pineapple', 'watermelon', 'eggplant']
fruits[:] = [] #删除全部list元素
[]