Python 7 list for dictionary, nested

List:

Basic format: variable name = [element 1, Element 2, Element 3]

Create: A = [' Visitor ', ' admin ', 19] or A = List ([' Armin ', ' admin ', 19]), which prefers to convert to a list of functions.

Directly define the first kind.

In judgment: If "Guest" in A: used to determine if a string visitor is included in a. The smallest unit that is judged here is the three elements in the list.

You cannot judge a more detailed character in an element.

If 9 in a[2]: used to determine if the number 9 is contained in the third element of the A list. This is used to determine only one of the elements in the list

Contains 9 of this character.

Index: a[0]

Slices: Same as String. For example A[1][1:3] If you write only to the first parenthesis, the smallest unit of the slice is the element in the list.

If a second parenthesis is written, the smallest unit is the character in the element.

Length: Len (A) The length of the list is the number of elements in the list. Rather than the number of characters.

To loop through a list element:

A = List (['Armin','admin',+]) i = 0 whilei <print(a[i]) i + = 1 

Append element: A.append ("ddd") adds an element to the tail of the list.

Insert element: A.insert (0, "the element to be inserted") means inserting the element to be inserted before the position No. 0 of the list A

Delete: A.remove (Element) but only the elements on the first match from left to right are deleted.

Del a[0] Deletes the elements in list A by location. Can be deleted using the Del a[0:] Slice.

Modified: a[0] = "ADSFASDF" modified to "ASDFASDF" for the No. 0-bit element of list A

For loop:

Basic structure:

A = ["admin","Guest", "+" inPrint (custom) #即可循环打印出列表A当中的所有元素. # break # Continue        

Dictionary: D = {key: value, key: Value}

Create: V = {"name1": "admin"

"Name2": "Guest"

}

Or:

V = Dict ({"name1": "admin"

"Name2": "Guest"

}）

Value: v[' name1 ') to remove the value corresponding to the ' name1 ' key in the dictionary V.

Add modified element: V[name3] = "hahaha" If the dictionary contains name3 then that is the modification, if not it will add Name3 in the dictionary.

Delete: Del d["Name3"]

For loop Fetch dictionary value:

　　　　fetch key: for custom in D: or for Custom in D.keys (): Print (Custom)

D = {    "name1":"admin""name2":"[' admin ', ' Mark ']" }inprint (AAA)              

value:for Custom in D.values () to show print (custom)

D ={"Name1 ": " admin"  "name2  ": " [' admin ', ' Mark ']< Span style= "COLOR: #800000" > "}for aaa in D.values (): #aaa是自定义的,. Values is a keyword. print (AAA) output: [ "admin ", mark "]admin   

　　　　Key-value pairs: for key,val in D.items (): The embodiment of print (Key,val) key,val is casually defined. Commas are required.

B{"Name1 ": " admin"  "name2  ": " [' admin ', ' Mark ']< Span style= "COLOR: #800000" > "}for key,val in D.items (): @.items is the keyword Key.val is custom, but the comma in it is required print (key,val) output: name1 adminname2 [" admin ", mark "        

For custom in D.items (): Similar to above, but output results

B{"Name1":"Admin","name2" [' admin ', ' Mark ']" }for aaa in D.items (): #aaa是自定义的,. Items is a keyword. print (AAA) output: ( "name2 ", [' admin ', ' Mark ']name1 ",  ' admin      

Nesting of lists and dictionaries:

List nested lists:

List = [‘Armin ",  ' admin", 1234,[ ' a  ", " b, ', 11armin ",  "admin", 1234, [ ' a ",  ' b, ", [one]]     

Dictionary nesting:

A_dict ={‘Key1‘:"Value1",‘Key2‘:{‘K1‘:‘V1‘,‘K2‘:[‘vv1 ",  ' vv2 ' "},  "key3 ": 886,  "key4": [ ' armin", 

Modifications to dictionaries and lists in nested:

A_dict ={‘Key1‘:"Value1",‘Key2‘:{‘K1‘:‘V1‘,‘K2‘:[‘Vv1‘,‘Vv2‘]},‘Key3': 886,‘Key4‘:[‘Armin‘,‘Admin ", [1,2,3],{" k41 ": " v41  ' }]} A_dict[ "key4"][3][ ' n "]=  "test" #向 Keys4 in the fourth element Add a key n value to test. a_dict[ "key4print (a_dict)            

Nested applications:

A_dict =[    {"Name" :"Armin","Pwd" :"123"}, {"Name" :"Admin","Pwd" :"123"}, {"Name" :"Acmin","Pwd" :"123"}]username = input ("Please enter user name:") Password = input ("Please enter your password:")For AAAin a_dict: if username = = aaa["name"] and password = = aaa["pwd"]: prin T (" not Easy ") else: print (" please check user name password ")   break  

Python 7 list for dictionary, nested