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How can I store reference to a variable within an array?
Consider the following code:
var a = 'cat';
var b = 'elephant';
var myArray = [a,b];
a = 'bear';
myArray[0] will still return 'cat'. Is there a way to store references in the array instead of clones, so that myArray[0] will return 'bear'?
While I agree with everyone else saying that you should just use myArray[0] = whatever, if you really want to accomplish what you're trying to accomplish you could make sure that all you variables in the array are objects.
var a = {animal: 'cat'},
b = {animal: 'elephant'};
var myArray = [a, b];
a.animal = 'bear';
myArray[0].animal is now 'bear'.
No. JavaScript doesn't do references in that way.
Nope, it is not possible. JavaScript doesn't support such references.
Only objects are stored as references. But I doubt it's what you want here.
$b = &$a then it will be true.
You've kind of answered your own question. If you want myArray[0] to equal bear, then set:
myArray[0] = "bear";
Even if your array holds references to objects, making a variable refer to an entirely different object would not change the contents of the array.
Your code does not modify the object variable a refers to. It makes variable a refer to a different object altogether.
Just like your JavaScript code, the following Java code won't work because, like JavaScript, Java passes references to objects by value:
Integer intOne = new Integer(1);
Integer intTwo = new Integer(2);
Integer[] intArray = new Integer[2];
intArray[0] = intOne;
intArray[1] = intTwo;
/* Make intTwo refer to a completely new object */
intTwo = new Integer(45);
System.out.println(intArray[1]);
/* output = 2 */
In Java, if you change the object referenced by a variable (instead of assigning a new reference to a variable) you get the behavior you desire.
Example:
Thing thingOne = new Thing("funky");
Thing thingTwo = new Thing("junky");
Thing[] thingArray = new Thing [2];
thingArray[0] = thingOne;
thingArray[1] = thingTwo;
/* Modify the object referenced by thingTwo */
thingTwo.setName("Yippee");
System.out.println(thingArray[1].getName());
/* output = Yippee */
class Thing
{
public Thing(String n) { name = n; }
private String name;
public String getName() { return name; }
public void setName(String s) { name = s; }
}
JavaScript not Java. However, Java and JavaScript are both pass by value where object references are also passed by value. Thus, in this specific case, I think your answer and explanation still stand. Consider adding some JavaScript examples as well just to be thorough. :)
myArray[0]='bear'. I can't find a reason why to create such reference.