• 列表的使用


    列表是我们最以后最常用的数据类型之一,通过列表可以对数据实现最方便的存储、修改等操作

    定义列表

    1 >>> names = ["Zhangsan","Lisi","Wangwu","Zhaoliu"]

    通过下标访问列表中的元素,下标从0开始计数

    1 >>> names[0]
    2 'Zhangsan'
    3 >>> names[2]
    4 'Wangwu'
    5 >>> names[-1] #-1表示最后一位
    6 'Zhaoliu'
    7 >>> names[-2]
    8 'Wangwu'

    切片:

     1 >>> names = ["Zhangsan","Lisi","Wangwu","Zhaoliu","Qianqi","Sunba"]
     2 >>> names[1:4]  #取下标1至下标4之间的数字,包括1,不包括4(顾头不顾尾)
     3 ['Lisi', 'Wangwu', 'Zhaoliu']
     4 >>> names[1:-1] #取下标1至-1的值,不包括-1
     5 ['Lisi', 'Wangwu', 'Zhaoliu', 'Qianqi']
     6 >>> names[0:3] 
     7 ['Zhangsan', 'Lisi', 'Wangwu']
     8 >>> names[:3] #如果是从头开始取,0可以忽略,跟上句效果一样
     9 ['Zhangsan', 'Lisi', 'Wangwu']
    10 >>> names[3:] #如果想取最后一个,必须不能写-1,只能这么写
    11 ['Zhaoliu', 'Qianqi', 'Sunba']
    12 >>> names[3:-1] #这样-1就不会被包含了
    13 ['Zhaoliu', 'Qianqi']
    14 >>> names[0::2] #后面的2是代表,每隔一个元素,就取一个
    15 ['Zhangsan', 'Wangwu', 'Qianqi']
    16 >>> names[::2] #和上句效果一样
    17 ['Zhangsan', 'Wangwu', 'Qianqi']

    追加:append

    1 >>> names = ["Zhangsan","Lisi","Wangwu","Zhaoliu","Qianqi","Sunba"]
    2 >>> names.append("我是新来的")
    3 >>> names
    4 ['Zhangsan', 'Lisi', 'Wangwu', 'Zhaoliu', 'Qianqi', 'Sunba', '我是新来的']

    插入:insert

     1 >>> names
     2 ['Zhangsan', 'Lisi', 'Wangwu', 'Zhaoliu', 'Qianqi', 'Sunba', '我是新来的']
     3 >>>
     4 >>> names.insert(2,"从Wangwu前面插入")
     5 >>> names
     6 ['Zhangsan', 'Lisi', '从Wangwu前面插入', 'Wangwu', 'Zhaoliu', 'Qianqi', 'Sunba', '我是新来的']
     7 >>>
     8 >>> names.insert(5,"插入到Wangwu后面")
     9 >>> names
    10 ['Zhangsan', 'Lisi', '从Wangwu前面插入', 'Wangwu', 'Zhaoliu', '插入到Wangwu后面', 'Qianqi', 'Sunba', '我是新来的']

    修改:

    1 >>> names
    2 ['Zhangsan', 'Lisi', '从Wangwu前面插入', 'Wangwu', 'Zhaoliu', '插入到Wangwu后面', 'Qianqi', 'Sunba', '我是新来的']
    3 >>> names[2] = "替补上场"
    4 >>> names
    5 ['Zhangsan', 'Lisi', '替补上场', 'Wangwu', 'Zhaoliu', '插入到Wangwu后面', 'Qianqi', 'Sunba', '我是新来的']

    删除:del

     1 >>> del names[2] #删除指定下标
     2 >>> names
     3 ['Zhangsan', 'Lisi', 'Wangwu', 'Zhaoliu', '插入到Wangwu后面', 'Qianqi', 'Sunba', '我是新来的']
     4 >>> del names[4]
     5 >>> names.remove("Wangwu") #删除指定列表元素
     6 >>> names
     7 ['Zhangsan', 'Lisi', 'Zhaoliu', 'Qianqi', 'Sunba', '我是新来的']
     8 >>> names.pop()  #默认删除最后一位,添加下标后效果等同del names[x]
     9 '我是新来的'
    10 >>> names
    11 ['Zhangsan', 'Lisi', 'Zhaoliu', 'Qianqi', 'Sunba']

    扩展:extend

    1 >>> names
    2 ['Zhangsan', 'Lisi', 'Zhaoliu', 'Qianqi', 'Sunba']
    3 >>> names2 = [1,2,3,4]
    4 >>> names.extend(names2)
    5 >>> names
    6 ['Zhangsan', 'Lisi', 'Zhaoliu', 'Qianqi', 'Sunba', 1, 2, 3, 4]

    统计:count

    1 >>> names = ["Zhangsan","Lisi"
    ,"Wangwu","Zhaoliu","Qianqi","Sunba","Wangwu"] 2 >>> names.count("Wangwu") 3 2

    排序:sort

    1 >>> names = ["!Zhangsan","123Lisi","$Wangwu","zhaoliu","Qianqi","Sunba"]
    2 >>> names.sort()
    3 >>> names
    4 ['!Zhangsan', '$Wangwu', '123Lisi', 'Qianqi', 'Sunba', 'zhaoliu'] #按ASC码顺序排列

    反转:reserse

    1 >>> names
    2 ['!Zhangsan', '$Wangwu', '123Lisi', 'Qianqi', 'Sunba', 'zhaoliu']
    3 >>> names.reverse()
    4 >>> names
    5 ['zhaoliu', 'Sunba', 'Qianqi', '123Lisi', '$Wangwu', '!Zhangsan']

    获取下标:index

    1 >>> names
    2 ['zhaoliu', 'Sunba', 'Qianqi', '123Lisi', '$Wangwu', '!Zhangsan']
    3 >>>
    4 >>> names.index("Qianqi")
    5 2

    清空: clear

    1 >>> names
    2 ['zhaoliu', 'Sunba', 'Qianqi', '123Lisi', '$Wangwu', '!Zhangsan']
    3 >>> names.clear()
    4 >>> names
    5 []
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  • 原文地址:https://www.cnblogs.com/gyf9527/p/8653860.html
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