列表、元组的基本操作

>>> names = [‘a‘,‘b‘,‘c‘,‘d‘]
>>> names
[‘a‘, ‘b‘, ‘c‘, ‘d‘]

>>> names
[‘a‘, ‘b‘, ‘c‘, ‘d‘]
>>> names[2]
‘c‘
>>> names[-1]
‘d‘

>>> names
[‘a‘, ‘b‘, ‘c‘, ‘d‘]
>>> names[1:3]
[‘b‘, ‘c‘]
>>> names[-3:-1]
[‘b‘, ‘c‘]
>>> names[-3:]
[‘b‘, ‘c‘, ‘d‘]
>>> names[::2] #后面的2表示步长
[‘a‘, ‘c‘]

>>> names
[‘a‘, ‘b‘, ‘c‘, ‘d‘]
>>> names.append(‘e‘) #表示在末尾追加元素
>>> names
[‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘]
>>> names.insert(1,‘A‘) #表示在指定位置插入元素
>>> names
[‘a‘, ‘A‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘]

>>> names
[‘a‘, ‘A‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘]
>>> names[1]=‘B‘
>>> names
[‘a‘, ‘B‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘]

>>> del names[1] #删除指定位置的元素
>>> names
[‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘]
>>> names.remove(‘c‘) #删除指定值得元素
>>> names
[‘a‘, ‘b‘, ‘d‘, ‘e‘]
>>> names.pop() #删除最后一个元素并返回该值
‘e‘
>>> names
[‘a‘, ‘b‘, ‘d‘]
>>> names.pop(0) #删除指定位置的元素并返回该值
‘a‘
>>> names
[‘b‘, ‘d‘]

>>> names
[‘b‘, ‘d‘]
>>> names
[‘b‘, ‘d‘]
>>> b=[1,2,3]
>>> names.extend(b)
>>> names
[‘b‘, ‘d‘, 1, 2, 3]

>>> names
[‘b‘, ‘d‘, 1, 2, 3]
>>> name1=names #这样的复制只是两个变量指向同一个地址，当一个发生改变，另一个也会改变
>>> name1
[‘b‘, ‘d‘, 1, 2, 3]
>>> names[1]=‘A‘
>>> names
[‘b‘, ‘A‘, 1, 2, 3]
>>> name1
[‘b‘, ‘A‘, 1, 2, 3]

------------------------------------------------------------------
>>> names
[‘b‘, [‘A‘, ‘B‘, ‘C‘], 1, 2, 3]
>>> names2 = names.copy() #这种情况属于浅复制，只会复制第一层的索引，也就是说只会复制出当前的值，至于当前值里面的值得可以被修改的，比如下面的列表里面的那个列表就发生了修改，而列表中的第一个值没有改变
>>> names2
[‘b‘, [‘A‘, ‘B‘, ‘C‘], 1, 2, 3]
>>> names[0]=1
>>> names[1][1]=‘hello‘
>>> names
[1, [‘A‘, ‘hello‘, ‘C‘], 1, 2, 3]
>>> names2
[‘b‘, [‘A‘, ‘hello‘, ‘C‘], 1, 2, 3]
#除了上述的浅复制还有如下几种方法
>>> names=[1,2,3,4]
>>> import copy #通过导入copy模块
>>> name1 = copy.copy(names)
>>> name1
[1, 2, 3, 4]
>>> name2=names[:]
>>> name2
[1, 2, 3, 4]
>>> name3 = list(names)
>>> name3
[1, 2, 3, 4]
------------------------------------------------------------------
>>> names
[1, [‘a‘, ‘b‘], 3, 4]
>>> import copy
>>> name1=copy.deepcopy(names) #使用copy模块中的deepcopy方法进行深复制，从下面的结果看来，值都不会发生改变
>>> name1
[1, [‘a‘, ‘b‘], 3, 4]
>>> names[0]=‘A‘
>>> names[1][1]=‘B‘
>>> names
[‘A‘, [‘a‘, ‘B‘], 3, 4]
>>> name1
[1, [‘a‘, ‘b‘], 3, 4]

>>> names=[1,2,1,3,4,3,2,1]
>>> names.count(1)
3

>>> names=[1,2,1,3,4,3,2,1]
>>> names.sort()
>>> names
[1, 1, 1, 2, 2, 3, 3, 4]
>>> names.reverse()
>>> names
[4, 3, 3, 2, 2, 1, 1, 1]

>>> names=[‘a‘,‘b‘,‘c‘]
>>> names.index(‘b‘)
1

>>> names=(‘a‘,‘b‘,‘c‘,‘c‘)
>>> names.count(‘c‘)
2
>>> names.index(‘b‘)
1