Python interface automation test framework (basic) -- common data types Dict

「 This is my participation 11 The fourth of the yuegengwen challenge 6 God , Check out the activity details ：2021 One last more challenge 」

Preface

The next two articles are about variable data types , Finally dict, From the author's experience , The order of common data types should be dict、list、str、tuple、bool( Often used as a judgment condition )、int.< Of course, others have different views >

Dictionaries

keyword ：dict, Symbol {}, It is a variable container model and can store any type of object ; With key:value Save data in the form of ,key： only , Non iteratable data types ：int float Boolean value Tuples &value： Can contain any data type ：int float str list tuple dict Boolean value

Create a dictionary

• Code demonstration ： The immutable data type is key

dict_1={}  #  Represents an empty dictionary 

dict_2={"a":"b"}

dict_3={(1,):2,1.1:2,True:False} 
 Copy code 

Value method

dict_1={"k1":"v1"}

dict_1[key] #  That is, get the specified key Value 

dict_1.get(key) # obtain key Value , There is no return none, It is more flexible than the previous dictionary 
 Copy code 

Additions and deletions

• Add to change ： The assignment operation , If key non-existent , It's new , The opposite is to modify

dict_1={}
dict_1["key"]="value" 

print(dict_1)={"key":"value"}
 Copy code 

• dict Delete except del Others are implemented through functions

dict_1={"k1":"v1","ke":"ve"}

v=dict_1.pop("k1")  #  Delete function , And return to delete key Of value

print(v) #  Output ：v1

dict_2=dict_1.popitem()  #  Randomly delete a group key：value And back to tuple

print(dict_2) #  Output ：("ke","ve")

clear() #  Empty dictionary   no return value , primary dict_1 Will become {}

del dict_1[key]  Delete the specified key
 Copy code 

• update The update function can only be dict type

dict1={"k1":"v1"}

dict1.update({1:2})

print(dict1) #  Output ：{'k1': 'v1', 1: 2}
 Copy code 

Built in functions

• items(), among dict The key value pair of becomes an element of a tuple , return list form , But it's not list data type , It is dict_items

dict1={"ke":"ve","k1":"v1"}

li=dict1.items()

print(li) #  Output ：dict_items([{"ke":"ve"},{"k1":"v1"}])
 Copy code 

• values(), obtain dict All of the objects value, With list form , But not of any kind , It is dict_values

dict1={"ke":"ve","k1":"v1"}

li=dict1.values() 

print(li) # dict_values(['ve', 'v1'])
 Copy code 

• keys(), obtain dict All of the objects key, With list form , But not of any kind , It is dict_keys

dict_1={"ke":"ve","k1":"v1"}

li=dict_1.keys()

print(li) #  Output ：dict_keys(['ke', 'k1'])
 Copy code 

• len() Calculate the length of the variable , stay dict Statistics in key Total of
• has_key(key) Used to determine key Whether there is dict In the object , Otherwise return to False

dict1={"k1":"1","a":"b","k1":"2"}

b=dict1.has_key("kk")

# Python 3.X  The method is not supported .
print b #  Output ：False
 Copy code 

Extended features

We know dict Type of key Must be the only , Immutable data types , If key Duplicate occurs , It only remembers the last value

dict1={"k1":"1","a":"b","k1":"2"}

print(dict1) #  Output ：{"k1":"2","a":"b"}
 Copy code