Python-list: List

A "list" is a value that contains a sequence of multiple words. The term "list value" refers to the list itself (which, as a value, can be saved in a variable, passed to a function)

list [' AA ', ' BB ', ' cc ', ' DD '] is a simple listing

1. Use list subscript to value

List =[' aa ', ' BB ', ' cc ', ' DD '

List[0]--aa

List[1]--bb

List[-1]--dd

2. Slice value (take one or more values from the list and return the result is a list)

List =[' aa ', ' BB ', ' cc ', ' DD '

list[:3]--[' AA ', ' BB ', ' CC ' #顾头不顾尾

list[:1]--[' AA ']

list[0:-1]--[' AA ', ' BB ', ' CC '

3. Get the length of the list with Len ()

list [' AA ', ' BB ', ' cc ', ' DD ']

Len (list)--4

4. Use subscript to change the values in the list

List =[' aa ', ' BB ', ' cc ', ' DD '

list[0]= ' AA '--[' AA ', ' BB ', ' cc ', ' DD ']

LIST[0]=LIST[1]----[' BB ', ' BB ', ' cc ', ' DD ']

5. List connections and list replication

list= [' AA ', ' BB ', ' cc ', ' DD ']

num=[' 11 ', ' 22 ', ' 33 ', ' 44 ']

list+num--[' AA ', ' BB ', ' cc ', ' dd ', ' 11 ', ' 22 ', ' 33 ', ' 44 ']

list+[' AA ', ' BB ']---[' aa ', ' BB ', ' cc ', ' dd ', ' AA ', ' BB ']

list*2--[' AA ', ' BB ', ' cc ', ' dd ', ' AA ', ' BB ', ' cc ', ' DD '

6. Delete the value from the list with Del

list= [' AA ', ' BB ', ' cc ', ' DD ']

del list[0]--[' BB ', ' cc ', ' DD ']

7. Use the list

Catanames = []
While True:
    Print (' Enter the name of the cat ' +str (len (catanames)) + ' (or enter nothing to stop.): ')
    name = str (input ())
    If name = = ':
        Break
    Catanames = Catanames+[name]
Print (' The Cat Names is: ')
For name in Catanames:
    Print (' +name ')

C:\Python27\python.exe c:/users/xiu/pycharmprojects/h5/day1/22.py
Enter the name of Cat0 (or enter nothing to stop.):
' Cat01 '
Enter the name of CAT1 (or enter nothing to stop.):
' cat02 '
Enter the name of CAT2 (or enter nothing to stop.):
' cat03 '
Enter the name of CAT3 (or enter nothing to stop.):
‘ ‘
The Cat names is:
cat01
cat02
cat03

Process finished with exit code 0

List for looping

list = [' cat001 ', ' cat002 ', ' cat003 ']
For I in range (len (list)):
    Print (' index ' + str (i) + ' in list is: ' + list[i])

C:\Python27\python.exe c:/users/xiu/pycharmprojects/h5/day1/22.py
Index 0in list is:cat001
Index 1in list is:cat002
Index 2in list is:cat003

8.in and not in operators

list= [' AA ', ' BB ', ' cc ', ' DD ']

print ' AA ' in List--true

print ' Aa1 ' in List--false

9. Assignment to variable enhancement (+ 、-、 *,/,%)

AA = 10
AA +=2       #aa = AA +2  output 12
AA-=2       #aa = aa-2   Output 10
AA *=2       #aa = AA */  output 20
AA/=2       #aa = aa/2   Output 10
AA%=2       #aa = aa% 2  output 0

10. Use the index () method to find the value in the list: Check element subscript based on element value

list= [' AA ', ' BB ', ' cc ', ' DD ', ' CC ']
Print list.index (' BB ')  #1
Print List.index (' cc ')  #2: If the list has multiple values of the same element, the first one is returned

11. Add a value to the list using the Append ()/insert () method

list= [' AA ', ' BB ', ' cc ', ' DD ']
List.append (' ee ')         #[' aa ', ' BB ', ' cc ', ' dd ', ' EE ']
List.insert (0, ' AA ')       #[' AA ', ' AA ', ' BB ', ' cc ', ' dd ', ' EE ']

12.remove () Remove a value from the list

list= [' AA ', ' BB ', ' cc ', ' DD ']
List.remove (' AA ')   #[' BB ', ' cc ', ' dd ') delete element value directly
Del list[0]         #[' cc ', ' DD ')    delete element value by subscript

13. Sort the values in the list using the sort () method (only the list of pure numbers, pure letters) can be sorted

list= [' DD ', ' cc ', ' BB ', ' AA ']
List.sort ()                      #[' aa ', ' BB ', ' cc ', ' DD '  default ascending order
List.sort (reverse=true)          #[' DD ', ' cc ', ' BB ', ' AA ']
List.sort (reverse=false)         #[' aa ', ' BB ', ' cc ', ' DD ']

list= [' DD ', ' cc ', ' BB ', ' AA ', ' AA ', ' BB ', ' cc ', ' DD ']
List.sort ()           #[' aa ', ' BB ', ' cc ', ' dd ', ' AA ', ' BB ', ' cc ', ' DD ', '  using ' ASCII character sorting ', so that uppercase letters are preceded by lowercase letters

　　

Python-list: List