Using keys in Java arrays?

[Valgarv]

A PHP example:

$arr = array("foo" => "bar", 12 => true);

echo $arr["foo"]; // bar
echo $arr[12];    // 1 

$arr["foo"] = "bar"
$arr[12] = 1

Can you do this with Java arrays? If so, how?

[Philwx]

Yeah it's called a HashMap/Hashtable.

The two are similar but Hashtable is safer for multiple threads. Other than that it doesn't matter which you use.


Your PHP program is actually implementing a hash map/table but it is hiding that fact from you. All you see is the good stuff, the input and output.

In Java it can be done but you must make a Hashtable and use its methods.

Hashtable myTable = new Hashtable();

myTable.put("foo", "bar");

// myTable.get("foo") would return the "bar" string

It's not implemented like an array though, as the items are not placed in any particular order. Regardless, they are returned in constant time (the best possible). It can be dumped into an array if needed, also.