Dictionary [Python] 09_Python basis of

1. dictionary definition

 And a list of differences

• The list is an ordered collection of objects
• A dictionary is unordered collection of objects

Dictionaries with  {}  is defined

• Key  key is the index
• Value  value data
• Keys  and  values  used between : dividing
• Key must be unique in
• Value may take any rational data, but can only use the key strings , numbers  , or tuple 

definition

Dictionary name = {key1: value1, key2: value2, key3: value4}

1 people = {"name": "小明",
2           "age": 18,
3           "height": 1.75}
4 print(people)  # {'name': '小明', 'age': 18, 'height': 1.75}

 

2. Operating dictionary

. 1 people = { " name " : " Bob " }
 2  Print (people)   # { 'name': 'Bob'} 
. 3  Print (people [ " name " ])   # Xiaoming 
. 4 people [ " name " ] = " John Doe "   # modify Dictionary 
. 5  Print (people)   # { 'name': 'John Doe'} 
. 6 people [ " Age "] = 18   # not the new 
. 7  Print(people)   # { 'name': 'John Doe', 'Age': 18 is} 
. 8  Print (. people POP ( " Age " ))   # delete an existing key pair deletion return value 
. 9  Print (people )   # { 'name': 'John Doe'} 
10  
. 11 Person = { ' name ' : ' John Doe ' , ' Age ' : 18 is }
 12 is  Print ( len (Person))   # 2 
13 is temp_dict = { " height " :1.75}
14 . Person Update (temp_dict)   # If duplicate keys, overwrites the previous value pairs 
15  Print (Person)   # 'name': 'John Doe', 'Age': 18 is, 'height': 1.75} 
16  
. 17  for  K  in Person:
 18 is      Print ( " % S -% S " % ( K , Person [ K ]))
 . 19  
20 is  "" " name - John Doe
 21 is  Age - 18 is
 22 is  height - 1.75 " ""

 

 

3. The combination of dictionary and a list of

More dictionaries can be set in a list

1 card_list = [
2     {"name": "张三",
3      "QQ": 123456,
4      "phone": 10010},
5     {"name": "李四",
6      "QQ": 654321,
7      "phone": 10086}
8 ]