Python list, tuples

Python list:

The format of the list is:

list=["Index1", "Index2", "#list为列表名", index1,index2,1,2 as a list element.

The above is a simple list, how to get the elements in the output list? ：

#列表每个元素都有个下标, get the element values from the list according to the subscript: list=["index1", "Index2", 1,2]print (list[1]) index2 #打印结果 # list element subscripts are calculated from 0, followed by 0,1,2,3 in order.    Print (list[2]) 1 #打印结果 # Prints the last value of the list: printed (List[-1]) 2 #打印结果 # Prints the second element of the list to the last element: print (list[1:]) ["Index2", Min] #打印结果 # Symbol: A fixed format for the list: before the start element position: After the last element of the final print position: After the position is not added, it represents the previous position from: Print to the last element of the list. #打印列表的第一个元素到倒数第二个元素: Print (list[0:-1]) ["Index1", "Index2", 1] #打印结果 # every 11 bits, prints the list element once: print (List[0::2]) ["Index1", 1] # Print results

Introduce the basic definition of the list, get the elements, the following is to introduce the list of the increase, delete, check, change:

Increase:

#首先定义一个列表: list=["Test", "book"] #在列表后追加元素: List.append ("Bike") print (list) ["Test", "book", "Bike"]# Append elements to an element in the list: List.insert (0, "bike") print (list) ["Bike", "Test", "book"] #打印结果

By deleting:

#定义一个列表: list=["Test", "book"] #删除列表中的 "test": List.remove ("Test") print (list) ["book"] #打印结果 # Delete the element labeled 3 in the list: List.pop (3) print (list) ["Test", +]

Check:

#定义一个列表: list=["Test", 1,1,2, "book"] #查找列表中名为test的元素: Print (List[list.index ("Test")) test #打印结果 #list.index ()  To get the subscript of an element, the list cannot print the element name directly, and it needs to be printed by subscript; #查找列表中名为1的元素的数量: Print (List.count (1)) 2 #打印结果 # View the length of the list: print (list, "\nlist length is : ", Len (list)) #len () to see the length of the string. ["Test", 1,1,2, "book"] #打印结果list length is:5 #打印结果

Change:

#定义一个列表: list=["Test", "book"] #将列表中第一个元素改为 "bike": list[0]= "Bike" print (list) ["Bike", and "book"] #打印列表 # will list "book "Bike": Modify=list.index ("book") list[modify]= "list" Print (list) ["Test", "bike"] #打印结果

Other operations:

#定义一个列表: list=["Test", "book"] #拷贝list, generate a new list2:list2=list.copy () #这个copy为浅拷贝, which is equivalent to a soft link inside Linux, when the elements in the list change , the elements in the List2 also change at the same time, #深拷贝, the deep copy is equivalent to the copy of Windows, the original list changes, List2 does not change: List2=list.deepcopy () #列表的反转输出: List.reverse () print ( list) [' Book ', 2, 1, ' Test '] #打印结果 # Merge: list=["Test",]list2=["book", 2,1, "Test"]list.extend (list2) print (l IST) [' Test ', ' book ', ' book ', 2,1, ' test '] #打印结果 # list nested: list=["Test", "book", ["book", 2,1, "Test"]]print (list) [' Test ', "," book ", [' book ', 2,1, ' Test ']] #打印结果 # Gets the list of elements in the list: print (List[-1][0]) book #打印结果 # list sort, int and STR strings cannot be performed: List=[3, 1,2,8]list.sort () print (list) [1, 2, 3, 8] #打印结果

Speaking of which, the list of related knowledge is basically over, the following is simply the tuple:

Tuples, in fact, is a list of read-only mode, tuples can not be modified, that is, only query, can not be added, deleted, change operation.

Definition of tuples:

R= ("Test", 3, "bike")

Tuples are similar to queries and lists, so this is not a demonstration.

Python list, tuples