关于Python之列表增删改查的方法
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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