这篇文章主要介绍关于Python之列表增删改查的方法,文中示例代码介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们一定要看完!

列表的查

a=["klvchen","tom","jack","james","lily","lucy"]print(a[1:4])

结果:

['tom','jack','james']

注意:

列表的切片的下标以 0 为开始。即: 下标0 --> klvchen,下标1 --> tom,..... 下标5 --> lucy。

列表的切换顾头不顾尾,例如:a [1:4],则不会取到列表下标为4的元素

从左到右,取到最后:

a=["klvchen","tom","jack","james","lily","lucy"]print(a[1:])

结果:

['tom','jack','james','lily','lucy']

从左到右,取到倒数第二个值:

a=["klvchen","tom","jack","james","lily","lucy"]print(a[1:-1])

结果:

['tom','jack','james','lily']

从左到右,隔一个去取:

a=["klvchen","tom","jack","james","lily","lucy"]print(a[1::2])

结果:

['tom','james','lucy']

从右到左,一个一个去取:

a=["klvchen","tom","jack","james","lily","lucy"]print(a[3::-1])

结果:

['james','jack','tom','klvchen']

从右到左去取

a=["klvchen","tom","jack","james","lily","lucy"]print(a[-2:-4:-1])

结果:

['lily','james']

列表的增

append 方法默认插到最后一个位置

a=["klvchen","tom","jack","james","lily","lucy"]a.append("mary")print(a)

结果:

['klvchen','tom','jack','james','lily','lucy','mary']

insert 方法将数据插入到任意一个位置

a=["klvchen","tom","jack","james","lily","lucy"]a.insert(1,"mary")print(a)

结果:

['klvchen','mary','tom','jack','james','lily','lucy']

extend 方法可在列表的末尾一次性追加另一个序列中的多个值

a=["klvchen","tom","jack"]b=["james","lily","lucy"]a.extend(b)print(a)

结果:

['klvchen','tom','jack','james','lily','lucy']

列表的改

a=["klvchen","tom","jack","james","lily","lucy"]a[1]="tom2"print(a)

结果:

['klvchen','tom2','jack','james','lily','lucy']a=["klvchen","tom","jack","james","lily","lucy"]a[1:3]=["tom2","jack2"]print(a)

结果:

['klvchen','tom2','jack2','james','lily','lucy']

列表的删

remove 方法

a=["klvchen","tom","jack","james","lily","lucy"]a.remove("tom")print(a)

结果:

['klvchen','jack','james','lily','lucy']

pop 方法

a=["klvchen","tom","jack","james","lily","lucy"]b=a.pop(1)print(a)print(b)

结果:

['klvchen','jack','james','lily','lucy']tom

注意 pop 方法会返回删除的元素

del 方法

a=["klvchen","tom","jack","james","lily","lucy"]dela[1]print(a)

结果:

['klvchen','jack','james','lily','lucy']a=["klvchen","tom","jack","james","lily","lucy"]delaprint(a)

结果:

NameError:name'a'isnotdefined

注意:del a 把列表a从内存删除了,所以打印 a 列表程序会报错

列表元素的统计

list=['a','a','b','c']res=list.count('a')print(res)

结果:

2

列表的排序

sort 方法

a=["klvchen","tom","jack","james","lily","lucy"]print(a)a.sort()print(a)

结果:

['klvchen','tom','jack','james','lily','lucy']['jack','james','klvchen','lily','lucy','tom']

reverse 方法

a=["klvchen","tom","jack","james","lily","lucy"]print(a)a.reverse()print(a)

结果:

['klvchen','tom','jack','james','lily','lucy']['lucy','lily','james','jack','tom','klvchen']

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