python 列表 的使用

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列表

列表的使用

names=["ZhangSan","Guyang","Xianghuaqiang","Yuanbiao"];

print(names);

运行结果：

打印列表、["ZhangSan", "Guyang", "Xianghuaqiang", "Yuanbiao"]

1、取列表中的第一个值

print(names[0]);列表的小标是从0开始的，所以下表应该是0。

1、ZhangSan

2、取列表中第二个和第三个值

print(names[1:3]);这个称之为切片，将一段数据从中取出。顾头不顾尾

2、["Guyang", "Xianghuaqiang"]

3、取列表中最后一个值

print(names[3]);最后一个名字的下表就是3

3、Yuanbiao

4、在不了解列表长度的情况下如何取出最后一个值？

print(names[-1]);﹣1就是取某个列表的最后一个值

4、Yuanbiao

5、如何取出最后两个值？

print(names[-2:]);因为列表的取值是自左至右的，所以要先写出最左侧值的下表值

5、["Xianghuaqiang", "Yuanbiao"]

6、取列表中的前三个值

print(names[0:3]);

print(names[:3]);如果前面是0的话，可以忽略，效果与上面相同

6、["ZhangSan", "Guyang", "Xianghuaqiang"]

6、["ZhangSan", "Guyang", "Xianghuaqiang"]

7、在列表中追加一个值

names.append("Liuliu")#往列表中追加值，默认在最后

["ZhangSan", "Guyang", "Xianghuaqiang", "Yuanbiao", "Liuliu"]

8、在列表中插入一个值

names.insert(1,"Liumm")#在列表中插入一个值(第一个参数表示下标值，第二个参数是想插入的值得名称)，每次只能插入一个值，不能批量插入

["ZhangSan", "Liumm", "Guyang", "Xianghuaqiang", "Yuanbiao"]

9、修改列表中的某一个值

names[2]="Maso"#修改列表中的某一个值，将列表中的guyang替换为Maso

["ZhangSan", "Guyang", "Maso", "Yuanbiao"]

10、在列表中删除一个值，有三种方法

names.remove("Liumm")#删除列表中的某一个值，直接写出名称

del names[1]#删除列表中的某一个值得第二种方法，写出下标值

names.pop()#如果不加下标值，默认删除列表中的最后一个值

["ZhangSan", "Guyang", "Xianghuaqiang", "Yuanbiao", "Liuliu"]

11、在列表中查找出某一个值的位置

print(names.index("Yuanbiao"))#找出列表中某一个值的位置

4

["ZhangSan", "Liumm", "Guyang", "Xianghuaqiang", "Yuanbiao", "Liuliu"]

12、将查找出的列表值进行输出

print(names[names.index("Yuanbiao")])#打印出列表中某一个值的名称

4

Yuanbiao

["ZhangSan", "Liumm", "Guyang", "Xianghuaqiang", "Yuanbiao", "Liuliu"]

13、统计在一个列表中的重复值的数量

print(names.count("Guyang"))#统计重名值的数量

["ZhangSan", "Liumm", "Guyang", "Xianghuaqiang", "Yuanbiao", "Guyang", "Liuliu"]

2

14、清空列表

names.clear()

print(names);

[]

15、列表翻转，逆序排列

names.reverse()#将列表的顺序进行逆序排列

print(names);

["ZhangSan", "Liumm", "Guyang", "Xianghuaqiang", "Yuanbiao", "Guyang", "Liuliu"]

["Liuliu", "Guyang", "Yuanbiao", "Xianghuaqiang", "Guyang", "Liumm", "ZhangSan"]

16、sort排序

names.sort()

print(names);

["ZhangSan", "Liumm", "Guyang", "Xianghuaqiang", "Yuanbiao", "Guyang", "Liuliu"]

["Guyang", "Guyang", "Liuliu", "Liumm", "Xianghuaqiang", "Yuanbiao", "ZhangSan"]

优先级为特殊符号、数字、大写字母、小写字母

["#@ZhangSan", "3Guyang", "Guyang", "Liuliu", "Liumm", "Yuanbiao", "xXianghuaqiang"]

[Finished in 0.2s]

17、extend，扩展列表，将列表进行合并,合并后原有列表依然存在

增加一个“name2”name2=[1,2,3,4]

names.extend(name2)#将name2与names列表进行合并

["#@ZhangSan", "Liumm", "3Guyang", "xXianghuaqiang", "Yuanbiao", "Guyang", "Liuliu"]

["#@ZhangSan", "Liumm", "3Guyang", "xXianghuaqiang", "Yuanbiao", "Guyang", "Liuliu", 1, 2, 3, 4] [1, 2, 3, 4]

[Finished in 0.2s]

del name2#合并后将已有的列表进行删除

["#@ZhangSan", "Liumm", "3Guyang", "xXianghuaqiang", "Yuanbiao", "Guyang", "Liuliu"]

["#@ZhangSan", "Liumm", "3Guyang", "xXianghuaqiang", "Yuanbiao", "Guyang", "Liuliu", 1, 2, 3, 4]

[Finished in 0.1s]

18、copy，列表复制

names=["#@ZhangSan","3Guyang","xXianghuaqiang","Yuanbiao","Guyang"];

name2=names.copy()

print(names);

print(name2);

["#@ZhangSan", "3Guyang", "xXianghuaqiang", "Yuanbiao", "Guyang"]

["#@ZhangSan", "3Guyang", "xXianghuaqiang", "Yuanbiao", "Guyang"]

[Finished in 0.2s]

如果在一个列表内插入了一个列表，这个列表内的值是不会被copy的，只是copy的它的内存值。

names=["#@ZhangSan","3Guyang","xXianghuaqiang",["ab","12"],"Yuanbiao","Guyang"];

names[2]="向华强"

names[3][0]="AB"

print(names);

print(name2);

["#@ZhangSan", "3Guyang", "向华强", ["AB", "12"], "Yuanbiao", "Guyang"]

["#@ZhangSan", "3Guyang", "xXianghuaqiang", ["AB", "12"], "Yuanbiao", "Guyang"]

[Finished in 0.1s]

19、如何完整克隆一份列表

import copy

name2=copy.deepcopy(names)

print(names);

print(name2);

["#@ZhangSan", "3Guyang", "xXianghuaqiang", ["ab", "12"], "Yuanbiao", "Guyang"]

["#@ZhangSan", "3Guyang", "xXianghuaqiang", ["ab", "12"], "Yuanbiao", "Guyang"]

[Finished in 0.2s]

20、步长切片

names=["#@ZhangSan","3Guyang","xXianghuaqiang",["ab","12"],"Yuanbiao","Guyang"];

print(names[0:-1:2])#0代表第一个值，-1代表最后一个值，步长值加2

print(names[::2])#第一个值和最后一个值的数字可以省略

运行结果相同

["#@ZhangSan", "xXianghuaqiang", "Yuanbiao"]

["#@ZhangSan", "xXianghuaqiang", "Yuanbiao"]

感谢阅读，欢迎在评论区中发表自己不同的观点

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