Re: How to delete an entry from a Map?

Eric Sosman <>
Fri, 16 Nov 2007 16:00:09 -0500
www wrote On 11/16/07 15:36,:


I cannot figure out how to delete an entry from a Map(HashMap). For
example, suppose I have a class Person and 3 objects of that
type(personA, personB and personC):

public class Person {
    private String name;


    public String getName{
        return name;

personA is with name of "John", personB and personC are with other names.

Map<Person> map = new HashMap<Person>();

//so easy to add to Map


//now, I want the map only has the guy with name of "John", i.e. I want
to delete personB and personC from map. I felt that it is so difficult.

    You say you're using a Map, but your code sample seems
to be using a Set (and calling it a Map).

    If it's a Map, you would have something like

    Map<String,Person> map = new HashMap<String,Person>();
    // add Persons:
    map.put(personA.getName(), personA);
    map.put(personB.getName(), personB);
    map.put(personC.getName(), personC);
    // remove two of them:

    If it's a Set, it would look like

    Set<Person> set = new HashSet<Person>();
    // add Persons:
    // remove two of them:


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