Such as in PHP:
<?php
$a = 'hello';
$$a = 'world';
echo $hello;
// Prints out "world"
?>
I need to create an unknown number of HashMaps on the fly (which are each placed into an arraylist). Please say if there's an easier or more Java-centric way. Thanks.
The best you can do is have a HashMap of HashMaps. For example:
Map<String,Map<String,String>> m = new HashMap<String,Map<String,String>>();
// not set up strings pointing to the maps.
m.put("foo", new HashMap<String,String>());
Map<String,Object> would fit better to match PHP's environment. Obviously checks of map.get("key") instanceof Object.class would have to be used for non string objects, for primitive types you would need to use their object form instead , i.e. map.put("key",new Integer(5));Its not called variable variables in java.
Its called reflection.
Take a look at java.lang.reflect package docs for details.
You can do all such sorts of things using reflection.
Bestoes,
jrh.
Java does not support what you just did in PHP.
To do something similar you should just make a List<Map<>> and store your HashMaps in there. You could use a HashMap of HashMaps.
A 'variable variable' in Java is an array or List or some sort of data structure with varying size.
No. You would do something like
List<Map<String,String> myMaps = new ArrayList<Map<String,String>>()
and then in your loop you would do:
Map<String,String> newMap = new Hashtable<String,String>();
//do stuff with newMap
myMaps.add(newMap);
$a = "hello";, then$$a="world";is equivalent to$hello="world";, it used the string as a variable name... this actually can be extremely powerful when used well, thanks to it, it made class builds for json encoding purposes a walk in the park, literally took 1 line to do with it; example:function addParam($key,$val){$this->${$key} = $val }. a new variable under the class gets created out of nothing at runtime.