table of Contents
I. Summary
- Sequence Type Definition
- Method sequential processing function and
- Tuple type and operating
- List type and operation
- Sequence type scenarios
Second, the sequence type is defined
Sequence is a set of elements has a relationship with a
- Sequence is the one-dimensional vector elements, it may be different types of elements
- Similar mathematical sequence of elements:
s0, s1, … , sn-1 - Guided by a number between elements, accessible by the subscript sequence specific element
Sequence is a base class
2.1 Definition of numbers
Third, the sequential processing function and method
| Operators and Applications | description |
|---|---|
| x in s | If x is an element sequence s, returns True, otherwise False |
| x not in s | If x is an element sequence s, returns False, otherwise True |
| s + t | Connecting the two sequences s and t |
| S n-or n- S | The replication sequence s n times |
| s[i] | Index, s is returned in the i-th element, i is the sequence number |
| s [i: j] or s [i: j: k] | Slice, returns i to j in steps of k in the sub-element of the sequence s |
Examples of sequence type operation 3.1
ls = ['python', 123]
ls[::-1][123, 'python']s = 'python123'
s[::-1]'321nohtyp'3.2 generic functions and methods type sequence
| Functions and methods | description |
|---|---|
| only (a) | Returns the length of the sequence s |
| min (s) | Returns the smallest element of the sequence s, s elements require comparable |
| max(s) | Returns the maximum element of the sequence s, s elements require comparable |
| s.index(x) 或s.index(x, i, j) | S return sequence from position i to j start position of the first occurrence of the element x |
| s.count(x) | Returns the total number of x s appear in sequence |
ls = ['python', 123]
len(ls)2s = 'python123'
max(s)'y'Fourth, the tuple type and operating
4.1 yuan group type definition
Tuple type is an extension sequence
- Tuple is a sequence type, once created can not be modified
- Use parentheses () or tuple () to create, between elements separated by commas,
- You can use or not use parentheses
creature = "cat", "dog", "tiger", "human"
creature('cat', 'dog', 'tiger', 'human')color = (0x001100, "blue", creature)
color(4352, 'blue', ('cat', 'dog', 'tiger', 'human'))4.2 yuan operating group type
Tuple inherit all common types of operation sequence
- Tuple inherits all generic sequence of operations of the type
- Tuples can not be changed because the creation, so there is no special operation
- With or without parentheses
creature = "cat", "dog", "tiger", "human"
creature[::-1]('human', 'tiger', 'dog', 'cat')color = (0x001100, "blue", creature)
color[-1][2]'tiger'Fifth, the list of types and operation
5.1 List type definition
The list is an extension of sequence type, very common
- List is a sequence type, can be modified at will to create
- 使用方括号 [] 或list() 创建，元素间用逗号 , 分隔
- 列表中各元素类型可以不同，无长度限制
ls = ["cat", "dog", "tiger", 1024]
ls| 函数或方法 | 描述 |
|---|---|
| ls[i] = x | 替换列表ls第i元素为x |
| ls[i: j: k] = lt | 用列表lt替换ls切片后所对应元素子列表 |
| del ls[i] | 删除列表ls中第i元素 |
| del ls[i: j: k] | 删除列表ls中第i到第j以k为步长的元素 |
| ls += lt | 更新列表ls，将列表lt元素增加到列表ls中 |
| ls *= n | 更新列表ls，其元素重复n次 |
ls = ["cat", "dog", "tiger", 1024]
ls[1:2] = [1, 2, 3, 4]
ls['cat', 1, 2, 3, 4, 'tiger', 1024]del ls[::3]
ls[1, 2, 4, 'tiger']ls * 2[1, 2, 4, 'tiger', 1, 2, 4, 'tiger']5.2 列表类型操作函数和方法
| 函数或方法 | 描述 |
|---|---|
| ls.append(x) | 在列表ls最后增加一个元素x |
| ls.clear() | 删除列表ls中所有元素 |
| ls.copy() | 生成一个新列表，赋值ls中所有元素 |
| ls.insert(i,x) | 在列表ls的第i位置增加元素x |
| ls.pop(i) | 将列表ls中第i位置元素取出并删除该元素 |
| ls.remove(x) | 将列表ls中出现的第一个元素x删除 |
| ls.reverse() | 将列表ls中的元素反转 |
ls = ["cat", "dog", "tiger", 1024]
ls.append(1234)
ls['cat', 'dog', 'tiger', 1024, 1234]ls.insert(3, "human")
ls['cat', 'dog', 'tiger', 'human', 1024, 1234]ls.reverse()
ls[1234, 1024, 'human', 'tiger', 'dog', 'cat']5.3 列表功能默写
5.3.1 题目
- 定义空列表lt
- 向lt新增5个元素 --> lt += [1,2,3,4,5]
- 修改lt中第2个元素
- 向lt中第2个位置增加一个元素
- 从lt中第1个位置删除一个元素
- 删除lt中第1-3位置元素
- 判断lt中是否包含数字0
- 向lt新增数字0
- 返回数字0所在lt中的索引
- lt的长度
- lt中最大元素
- 清空lt
5.3.2 答案
- lt = []
- lt += [1,2,3,4,5]
- lt[2] = 6
- lt.insert(2, 7)
- del lt[1]
- del lt[1:4]
- 0 in lt
- lt.append(0)
- lt.index(0)
- len(lt)
- max(lt)
- lt.clear()
六、序列类型应用场景
数据表示：元组 和 列表
- 元组用于元素不改变的应用场景，更多用于固定搭配场景
- 列表更加灵活，它是最常用的序列类型
- 最主要作用：表示一组有序数据，进而操作它们
6.1 元素遍历
for item in ls/tp :
<语句块>6.2 数据保护
- 如果不希望数据被程序所改变，转换成元组类型
ls = ["cat", "dog", "tiger", 1024]
lt = tuple(ls)
lt('cat', 'dog', 'tiger', 1024)七、单元小结
- 序列是基类类型，扩展类型包括：字符串、元组和列表
- Tuple with () and tuple () to create, create a list with [] and set ()
- Tuple operation sequence substantially identical to the operation
- List of operations in sequence on the basis of the operation, an increase of more flexibility