Python Automation 3.0-------Learning path-------List

You can think of a list in Python as a sequence of arbitrary pairs of images, as long as you put the required parameter values into brackets [], just like this:

names = [' Ada ', ' Amy ', ' Ella ', ' Sandy ']

The list can contain different types of images, and nesting is also supported:

For example a = [' A ', 567,[' ADC ', 4,], (on)]

This list contains the elements of strings, integers, tuples, and a list of nested lists.

To modify a value in a list of lists

The list is ordered and can be modified by the Python list subscript to modify the value at a particular location. The following is an example of how to modify a list parameter, as described below:
>>>a = [1,9,9]
>>>a [0] = 9
>>>a
[9,9,9]
The modification of a list can also be viewed as an operation that assigns a value to a specific location.

Python List Delete operation

python list deletion the most commonly used methods are three: Del, remove, pop, and the use of methods and uses are not the same, here first understand the next del this is the most convenient entry-level list delete operation method.

The existing List names = [' Ada ', ' Amy ', ' Ella ', ' Sandy '], the requirement is to remove the above list of ' Amy ', the idea is: first know ' Amy ' in the list names in the index position, followed by Del this method to delete. The list del methods are used in the following ways:

>>>names = [' Ada ', ' Amy ', ' Ella ', ' Sandy ']
>>>del Names[1]
>>>names
[' Ada ', ' Ella ', ' Sandy ']

>>> list = [] #定义一个空列表
>>> list.append (1) #向列表中添加成员
>>> List.count (2) #计算2在列表中出现的次数
0
>>> List.extend ([2, 3, 5, 4]) #向列表中添加一个列表
>>> List #列表值被改变
[1, 2, 3, 5, 4]
>>> List.index (5) #获得5在列表中的位置
3
>>> List.insert (2, 6) #从0开始, that is, insert 6 in 3rd member, and the other members move back in the first place
>>> List
[1, 2, 6, 3, 5, 4]
>>> List.pop (2) #删除列表中第3个成员
6
>>> List
[1, 2, 3, 5, 4]
>>> List.remove (5) #删除列表中的5
>>> List
[1, 2, 3, 4]
>>> List.reverse () #颠倒列表的顺序
>>> List
[4, 3, 2, 1]
>>> List.sort () #将列表中的成员重新排序
>>> List
[1, 2, 3, 4]

The second piece of code:

#创建一个初始有两个字符串和一个整数的列表

>>> book = ["Python", "development", 8]

#在列表尾部添加另一个整数
>>> Book.append (2008)

#在第二个位置上插入一个字符串 (subscript 1)
>>> Book.insert (1, "web")
>>> Book
[' Python ', ' web ', ' development ', 8, 2008]

#获取头三个元素的一个切片
>>> book[: 3]
[' Python ', ' web ', ' development ']

#成员检查
>>> "Django" in the book
False

#无论元素的位置 to remove it from the list. (explicitly remove an object)
>>> Book.remove (8)

#根据位置 (i.e. subscript) remove (and return) an element
>>> Book.pop (-1)
2008
>>> Book
[' Python ', ' web ', ' development ']

How to use #展示复制操作符 *
>>> Book * 2
[' Python ', ' web ', ' development ', ' python ', ' web ', ' development ']

#用另一个列表扩展本列表
>>> Book.extend (["with", "Django"])
>>> Book
[' Python ', ' web ', ' development ', ' with ', ' Django ']

Common list Action methods

List.append (): Append member

List.count (x): Calculates the number of occurrences of a parameter X in a list

List.extend (L): Append another list to the list L

List.index (x): Gets the position of the parameter X in the list

List.insert (): Inserting data into the list

List.pop (): Remove a member from the list (deleted by subscript)

List.remove (): Remove a member from the list (delete directly)

List.reverse (): Reverses the order of the members in the list

List.sort (): Sort members in a list

Python Automation 3.0-------Learning path-------List