Java data Structure HashSet and HashMap (Java Core Volume Ⅰ reading notes)

Increase

Delete

The Remove method allows you to delete a specified element.

Find

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HashSet can neither use the index of 0 1 2 3 to determine the value of an element, nor use key to determine the value of an element

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HashSet like this ["AA", "BB"] grow into such a data structure

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HashMap grow into such {a=123, B=hello}

Jsonobject very much like {"A": 123, "B": null}

*hashmap*	*hashset*
HASHMAP implements the Map interface	HashSet implements the set interface
HashMap Store key value pairs	HashSet Only Store objects
Use the put () method to put elements into a map	Use the Add () method to put an element into a set

HashMap Faster, Because a unique key is used to get the object

HashSet more slowly than HashMap.

Java data Structure HashSet and HashMap (Java Core Volume Ⅰ reading notes)