How to compine two hash tables?

[Sultan Al-Yahyai]

Hell,
1) I have two hash tables say ht1, ht2
I need the contents of ht2 to me moved/coppied to the end of ht1, how to do so?

regards

[Jeroen Wenting]

get the keys from t2.
Iterate over those, and insert the values retrieved into t1.
Something like

Enumeration e = t2.keys();
while (e.hasMoreElements())
{
    Object o = e.nextElement();
    t1.put(o, t2.get(o));
}

Remember that this will replace any value from t1 that has the same key as another value from t2.

[Henry Wong]

You can't control the location of the entry in the map, and you have issues with duplicate keys, but I think this should work:

 t1.putAll(t2); 

[Robert Hayes]

Try putall() and/or read the java.util docs...

[Jeroen Wenting]

doh, missed that one

[Sultan Al-Yahyai]

Thank you all,

t1.putAll(t2); Didn't work
becuase method is not defined .putall(hashtable)!

but
Enumeration e = t2.keys();
while (e.hasMoreElements())
{Object o = e.nextElement();
t1.put(o, t2.get(o));
}
worked fine
thanks

[Sultan Al-Yahyai]

Hi,
Also I tried this one and it worked
Enumeration e=t1.elements();
Enumeration k=t1.keys();
while ( k.hasMoreElements() )
{ t2.put(k.nextElement(),e.nextElement());
}

[Robert Hayes]

Hashtable implements the Map interface, so it should work:

    public static void main(String[] args) {
    
        Hashtable ht1 = new Hashtable();
        ht1.put("1", "1");
        ht1.put("2", "2");
 
        Hashtable ht2 = new Hashtable();
        ht2.put("3", "3");
        ht2.put("4", "4");    
    
        ht1.putAll(ht2);
        
        Enumeration it = ht1.elements();
        while (it.hasMoreElements()) {
            System.out.println(it.nextElement());
        }
    }

[Jeroen Wenting]

Originally posted by Sultan AL-Yahyai:
Thank you all,

t1.putAll(t2); Didn't work
becuase method is not defined .putall(hashtable)!

putall isn't there, but putAll is.
Unless you're using a really really old compiler that is, 1.1 or earlier.