• python 列表的增,删,改,查以及嵌套


    列表

    列表-----list-----容器(有序,可变,支持索引)

    列表:存储数据,支持的数据类型很多(字符串,数字,布尔值,列表,集合,元组,字典)
    #定义一个列表
    lst = ["123","常青藤","九月风",123,True]
    #用逗号分隔的是一个元素
    print(lst[0])
    print(id(lst[0])) #id获取对象的内存地址
    
    lst = ["123","常青藤","九月风",123,True]
    lst [0] = "996"
    print(lst)
    #输出  ["996","常青藤","九月风",123,True]
    
    #字符串是不可变的数据
    s = "alex" # 字符串是不可变数据
    s = "wusir"
    s[0] = "b"
    print(s)
    

    增加

    1)追加:在列表的最后位置添加一个内容,关键词 append
    lst = ["123","常青藤","九月风",123,True]
    lst.append("冬日雪")
    print(lst)
    #输出 ['123', '常青藤', '九月风', 123, True, '冬日雪']
    
    2) 插入:以后尽量不要使用(当数据量比较大的时候会影响效率)关键字词 insert
    lst = ["123","常青藤","九月风",123,True]
    lst.insert(1,"冬日雪")
    print(lst)
    #输出  ['123', '冬日雪', '常青藤', '九月风', 123, True]
    
    3)迭代添加 关键词 extend(”可迭代的内容)
    lst = ["123","常青藤","九月风",123,True]
    lst.extend("夏季的雨")
    print(lst)
    # 输出 ['123', '常青藤', '九月风', 123, True, '夏', '季', '的', '雨']
    

    删除

    1)默认删除最后一个 关键词 pop
    有返回值返回的是被删除的元素
    dtu = ["123","常青藤","九月风",123,True]
    dtu.pop()
    print(dtu)
    # 输出 ['123', '常青藤', '九月风', 123]
    
    2)通过指定索引进行删除 关键词 pop(数字)
    lta = ["123","常青藤","九月风",123,True]
    lta.pop(2)
    print(lta)
    #输出 ['123', '常青藤', 123, True]
    
    3) 移除 ,通过元素名字进行删除 关键词 remove(元素名)
    lta = ["123","常青藤","九月份",123,True]
    lta.remove(123)
    print(lta)
    #输出 ['123', '常青藤', '九月份', True]
    
    4)通过索引删除 关键词 del
    lta = ["123","常青藤","九月份",123,True]
    del lta[1]
    print(lta)
    #输出 ['123', '九月份', 123, True]
    
    通过切片删除
    lta = ["123","常青藤","九月份",123,True]
    del lta[0:2]
    print(lta)
    #输出 ['九月份', 123, True]
    
    通过步长删除
    lta = ["123","常青藤","九月份",123,True,"夏日雨",False]
    del lta[0:5:2]
    print(lta)
    # 输出 ['常青藤', 123, '夏日雨', False]
    
    清空 (关键字 clear)
    lta = ["123",123,"春日雨","夏日阳","秋日果","冬日雪"]
    lta.clear()
    print(lta)
    # 输出 []
    

    改(元素可以超出切片的位数)

    lta = ["123","常青藤","九月份",123,True,"夏日雨",False]
    lta[1] = "冬日雪"
    print(lta)
    #输出['123', '冬日雪', '九月份', 123, True, '夏日雨', False]
    
    lta = ["123","常青藤","九月份",123,True,]
    lta[1:3] = "冬日雪"
    print(lta)
    #输出['123', '冬', '日', '雪', 123, True]
    
    lta = ["123","常青藤","九月份",123,True,]
    lta[1:4] = 12,13,14,15,16
    print(lta)
    #输出 ['123', 12, 13, 14, 15, 16, True]
    
    lta = ["123","常青藤","九月份",123,True,]
    lta[1:4:2 ]="12"
    print(lta)
    #输出 ['123', '1', '九月份', '2', True]
    
    • 步长不为1的必须要一一对应,多一个不行,少一个也不行

    for循环
    lta = ["123","常青藤","九月份",123,True,]
    for i in lta:
    	print(i)
    #输出
    123
    常青藤
    九月份
    123
    True
    

    列表的嵌套

    取值通过索引进行取值,一层一层的进行查找
    lst = [1,"alex","999","小东北","渣渣",
           ["大黑",["小七",["我帅吗"],"大煎饼","掉井盖","三金片"],
        "海棠","海马",["太白金星","女神","九月",["110"]]]]
    print(lst[-1][1][1][0])
    #输出 我帅吗
    
    • 不管什么类型进行切片的时候获取都到都是源数据类型
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  • 原文地址:https://www.cnblogs.com/lvtaohome/p/11215989.html
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