Python_列表方法

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Python_列表方法

1. 方法

2. 例子

（1）增加

1 >>> L = list('abc')
2 >>> L
3 ['a', 'b', 'c']
4 >>> s = 'def'

1 >>> L.append(s)
2 >>> L
3 ['a', 'b', 'c', 'def']

1 >>> L.extend(s)
2 >>> L
3 ['a', 'b', 'c', 'd', 'e', 'f']

1 >>> L.insert(1, s)
2 >>> L
3 ['a', 'def', 'b', 'c']

（2）删除

del，pop，remove

1 >>> L = ['a', 'b', 'c']

1 >>> del L[1]
2 >>> L
3 ['a', 'c']

1 >>> print(L.pop(1))
2 b
3 >>> L
4 ['a', 'c']

1 >>> L.remove('b')
2 >>> L
3 ['a', 'c']

三种清空方式的比较

　　参考地址：https://www.cnblogs.com/BackingStar/p/10986775.html

1 >>> L = list('abc')
2 >>> first = []
3 >>> last = []
4 >>> for i in L:
5     　　first.append(i)
6     　　last.append(first)
7     　　first = []
8 >>> last
9 [['a'], ['b'], ['c']]

1 >>> L = list('abc')
2 >>> first = []
3 >>> last = []
4 >>> for i in L:
5     　　first.append(i)
6     　　last.append(first)
7     　　first.clear()
8 >>> last
9 [[], [], []]

1 >>> L = list('abc')
2 >>> first = []
3 >>> last = []
4 >>> for i in L:
5     　　first.append(i)
6     　　last.append(first)
7     　　first *= 0
8 >>> last
9 [[], [], []]

（3）修改

1 >>> L= ['a', 'b', 'c']
2 >>> L[1] = 'z'
3 >>> L
4 ['a', 'z', 'c']

（4）查找

1 >>> L = list('abcb')
2 >>> 'b' in L
3 True
4 >>> 'z' not in L
5 True
6 >>> L.index('b')
7 1

（5）计数

1 >>> L = list('abcb')
2 >>> L.count('b')
3 2

（6）重排

1 >>> L = list('bfeacd')
2 >>> L
3 ['b', 'f', 'e', 'a', 'c', 'd']

1 >>> L.reverse()
2 >>> L
3 ['d', 'c', 'a', 'e', 'f', 'b']

1 >>> L.sort()
2 >>> L
3 ['a', 'b', 'c', 'd', 'e', 'f']

1 >>> print(sorted(L))
2 ['a', 'b', 'c', 'd', 'e', 'f']
3 >>> L
4 ['b', 'f', 'e', 'a', 'c', 'd']

（7）浅拷贝

1 >>> l1 = list('abc')
2 >>> l2 = l1.copy()
3 >>> id(l1) == id(l2)
4 False
5 >>> id(l1[0]) == id(l2[0])
6 True

注：浅拷贝和深拷贝的区别，详情见https://www.cnblogs.com/shz-blog/p/12451730.html

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