Python 学习笔记【09】列表、元组

　　定义列表

1 names = ["Zhangyang", "Guyun", "Xiangpeng", "Xuliangchen"]

　　通过下标取列表中的值

1 print(names[0], names[2])

　　切片:取多个元素

 1 print(names[1:3])  # 取第二个到第三个值  注：顾头不顾尾
 2 
 3 print(names[0:3]) # 取第一个到第三个值
 4 
 5 print(names[-1])  # 取最后一个值
 6 
 7 print(names[-2])  # 取倒数第二个值
 8 
 9 print(names[-3:-1])  # 取倒数第三个到倒数第二个值  注：从左往右取值
10 
11 print(names[-2:])  # 取倒数第二个到倒数最后一个值  注：省略冒号后的值，取到最后一个
12 
13 print(names[:3])  # 取第一个到第三个值  注：省略冒号前的值，从第一个开始取值
14 
15 print(names[:])

　　追加元素

1 names.append("Leihaidong")

　　插入元素

1 names.insert(1, "Chenzhonghua")
2 names.insert(3, "Xinzhiyu")

　　修改元素

1 names[2] = "Xiedi"

　　删除元素

1 names.remove("Chenzhonghua")  # 方法一
2 
3 del names[1]  # 方法二
4 
5 names.pop()  # 无下标，默认删除最后一个
6 
7 names.pop(1)  # 方法三

　　查找元素

1 print(names.index("Xiedi"))
2 
3 print(names[names.index("Xiedi")])

　　统计元素

1 print(names.count("Chenzhonghua"))

　　清空列表

1 names.clear()

　　反转列表

1 names.reverse()

　　排序列表

1 names.sort()

　　扩展列表

names = ["Zhangyang", "Guyun", "Xiangpeng", "Chenzhonghua", "Xuliangchen"]

names2 = [1, 2, 3, 4]

names.extend(names2)

print(names, names2)

　　删除列表

1 del names2

　拷贝列表

1 names = ["Zhangyang", "Guyun", "Xiangpeng", "Chenzhonghua", "Xuliangchen"]
2 
3 names2 = names.copy()
4 
5 print(names)
6 
7 print(names2)

　　拷贝列表为浅复制，只复制一层，深层指向内存地址

 1 names = ["Zhangyang", "Guyun", "Xiangpeng", ["alex", "jack"], "Chenzhonghua", "Xuliangchen"]
 2 
 3 names2 = names.copy()
 4 
 5 names[2] = "向鹏"
 6 
 7 names[3][0] = "ALEXANDER"
 8 
 9 print(names)
10 
11 print(names2)

　　如果列表赋值给列表，则只会指向内存地址，与字符串及数字赋值不同

 1 names = ["Zhangyang", "Guyun", "Xiangpeng", ["alex", "jack"], "Chenzhonghua", "Xuliangchen"]
 2 
 3 names2 = names
 4 
 5 names[2] = "向鹏"
 6 
 7 names[3][0] = "ALEXANDER"
 8 
 9 print(names)
10 
11 print(names2)

　　深层复制，导入copy模块

 1 import copy
 2 
 3 names = ["Zhangyang", "Guyun", "Xiangpeng", ["alex", "jack"], "Chenzhonghua", "Xuliangchen"]
 4 
 5 names2 = copy.deepcopy(names)  # 深Copy，ames2 = copy.copy(names)  为浅Copy
 6 
 7 names[2] = "向鹏"
 8 
 9 names[3][0] = "ALEXANDER"
10 
11 print(names)
12 
13 print(names2)

　　列表内元素的循环

1 names = ["Zhangyang", "Guyun", "Xiangpeng", ["alex", "jack"], "Chenzhonghua", "Xuliangchen"]
2 
3 for i in names:
4     print(i)

　　跳跃切片

1 names = ["Zhangyang", "Guyun", "Xiangpeng", ["alex", "jack"], "Chenzhonghua", "Xuliangchen"]
2 
3 print(names[0:-1:1])  # 从第一个值开始，到倒数第二个，每跳跃一个值切片

　　省略写法

1 names = ["Zhangyang", "Guyun", "Xiangpeng", ["alex", "jack"], "Chenzhonghua", "Xuliangchen"]
2 
3 print(names[::2])  # 从第一个值开始，到最后一个，每跳跃一个值切片

1 names = ["Zhangyang", "Guyun", "Xiangpeng", ["alex", "jack"], "Chenzhonghua", "Xuliangchen"]
2 
3 print(names[:])  # 从第一个值开始，到最后一个

　　浅Copy的三种方式

1 import copy
2 
3 person = ['name', ['a', 100]]
4 
5 p1 = copy.copy(person)
6 p2 = person[:]
7 p3 = list(person)

　　浅Copy的应用实例

 1 import copy
 2 
 3 person = ['name', ['saving', 100]]
 4 
 5 p1 = person[:]
 6 p2 = person[:]
 7 
 8 p1[0] = 'husband'
 9 p2[0] = 'wife'
10 
11 p1[1][1]=50
12 
13 print(p1)
14 print(p2)

　　元组

　　元组是存一组数，只是它一旦创建，便不能再修改，所以又叫只读列表

　　它有2个方法，一个是count，一个是index

1 names = ('jack', 'Alex')