Features of the dictionary:
key-value structure
The key must be hashable, must be an immutable data type, and must be unique
Can store any number of values, can be modified, can not be unique
disorder
Find fast
dict_fruit = {'apple':'apple','banana':'banana','cherry':'cherry','avocado':'avocado','watermelon':'watermelon'}
"apple" in dict_fruit >>> True # Determine if it is in the dictionary
for key in dict_fruit: >>> apple,banana,cherry,avocado,watermelon # Traverse the keys in the dictionary (the default traversal is the same as for key in res.keys():) [find the value of values through this]
for value in res.values(): >>> apple, banana, cherry, avocado, watermelon #traverse the value in the dictionary
for key,value in dict_fruit.items(): >>> apple apple, banana banana, cherry cherry, avocado avocado, watermelon watermelon # Traverse the keys and values in the dictionary [basically not used]
Increase:
dict_fruit["pineapple"] = "pineapple"
delete:
dict_fruit.pop["apple"] #Delete and return the deleted value
dict_fruit.popitem() #Randomly delete the values in the array
change:
dict_fruit["apple"] = "苹果1"
Find:
dict_fruit["apple"] #If the value does not exist, report an error
dict_fruit.get("apple") #get method lookup returns empty if it does not exist
dict_fruit.keys() # List all key values
dict_fruit.values() # List all values of value
dict_fruit.items() # put the key and value in the tuple
dict_fruit.update(res) #fill the res dictionary to the value of the key in dict_update
dict_fruit.setdefault(2,3) #Create a new key If there is one in the created key dictionary, return the value of the original key
dict.fromkeys(["a","b","c"],"xhl") #Batch generation of dictionaries of the same value