Python built-in ordered collection: list and tuple yes, one variable, one immutable

Python's built-in data types are lists: List:#注释list是一种可变的有序的集合, you can add and remove elements at any time

The elements in the list can be different data types such as integers, strings, nested lists

len( )Function: Gets the number of list elements

classmates . Append ( ' element ')   function: Append new element to list footer

classmates.insert(1, ‘元素‘)函数：通过索引得方式将新的元素追加至指定位置

classmates[]: by indexing the elements of each location

< Code>pop (i) function    : to delete the element at the specified position, where i is the index position

classmates[ 1]= ‘Sarah‘ ：直接赋值给对应的索引位置替换元素

Case 1: For example, List all the classmates in the class name, you can use a list to represent, as follows: Classmates variable, is a list:

>>> classmates = [‘Michael‘, ‘Bob‘, ‘Tracy‘]

 >>> classmates

 < Span class= "string" >[  ' Michael ',   ' Bob ',   ' Tracy ']  
  
 >>> Len ( Classmates)    #列出元素个数   
 3     
 
            

    #用索引来访问list中每一个位置的 element, remember that the index is starting from  0       
   #当索引超出了范围时 , Python will report a  indexerror  error, so to ensure that the index does not cross over, you can 1]    get it backwards.  

>>> classmates[0] ‘Michael‘>>> classmates[1]‘Bob‘>>> classmates[2]‘Tracy‘>>> classmates[3]

>>> classmates[-1]
‘Tracy‘

#追加新元素到末尾

>>> classmates.append(‘Adam‘)>>> classmates[‘Michael‘, ‘Bob‘, ‘Tracy‘, ‘Adam‘]

#通过索引得方式将新的元素插入到指定的位置，比如索引号为1的位置

>>> classmates.insert(1, ‘Jack‘)>>> classmates[‘Michael‘, ‘Jack‘, ‘Bob‘, ‘Tracy‘, ‘Adam‘]

#要删除指定位置的元素，用pop(i)方法，其中i是索引位置：

>>> classmates. Pop ( 1)' Jack '>>> classmates[   ' Michael ',   < Span style= "Font-family:microsoft Yahei; Font-size:13px "> Tracy ']  
 
   #将指定元素替换成别的元素 can be assigned directly to the corresponding index position   
 
 >>> classmates[1] =  ' Sarah ' 
 >>> classmates [ ' Tracy ']             

< Strong> 
 #list里面的元素的数据类型也可以不同, the list element can also be another list 
 #要拿到  ' php '  can write Span style= "COLOR: #ff0000" >  p[1]   or   s[2][1]  , So  s  can be seen as a two-dimensional array, similar to three-dimensional, four-dimension ... arrays, but rarely used.  
   
  #       to note that  s  has only 4 elements, where  s[2]  Another list, which is easier to understand if you disassemble the    
 
 >>> L = [ ' Apple ', 123,      [‘asp‘, ‘php‘]，True]
>>> len(s)4>>> p = [‘asp‘, ‘php‘]>>> s = [‘python‘, ‘java‘, p, ‘scheme‘]

#空数组
>>> L = [] 
>>> len(L) 
0 

Another ordered list in Python is called a tuple: tuple: #tuple和list非常类似, but the tuple does not allow additions and deletions, and so on. When defined, the elements of a tuple must be determined

#比如同样是列出同学的名字

#索引指定位置元素与list的方式相同

#只有1个元素的tuple定义时必须加一个逗号 , , to eliminate ambiguity:

>>> classmates = (‘Michael‘, ‘Bob‘, ‘Tracy‘)

>>> classmates = [i]


# #最后来看一个 "mutable" tuple: On the surface, the elements of a tuple do change, but not the elements of a tuple, but the elements of the list

　>>> t = (‘a‘, ‘b‘, [‘A‘, ‘B‘])

 > >> t[2][0] = ' X '

>>> t[2][1] = ‘Y‘>>> t(‘a‘, ‘b‘, [‘X‘, ‘Y‘])

list和tuple是Python内置的有序集合，一个可变，一个不可变。根据需要来选择使用它们。

Python built-in ordered collection: list and tuple yes, one variable, one immutable