Cast Object[] to String[]

[AlistairMonkeyFinger]

Is there an easy way to convert (cast) a Object array to a String array ?

thanks Alistair

 

[thekobbler]

You can't cast the array, so you'll have do something like..

String[] strArray = new String[array.length];
for(int i=0;i<array.length;i++) strArray = (String)array;

where array is an Object[] where each element is a String.

 

[bigDaftie]

You could do something like this and write a toString method for your object. Then you would get a string representation of your object

class MyObject{

private String name;

public MyObject(String aName){
name=aName;
}//constructor

//toString method...
public String toString(){
return new String(name);
}
}//class

Then in your code you can just call the toString method like this...

MyObject anObject;

Object[] objArray={new MyObject(&quot;1&quot,new MyObject(&quot;2&quot};
String[] strArray = new String[objArray.length];

for(int i=0;i<strArray.length;i++){
//call the toString method you write for your object
strArray = objArray.toString();
System.out.println(&quot;&quot;+strArray);
}

There is a toString method in the class Object, which brings back the name of the class and it's memory location as a string eg MyObject@253498

 

[bigDaftie]

hmmmm seems to be taking a few characters away on posting, The square brackets that refer to the array location clashing with markup. whoops!
Supposed to read like this...

for(int i=0;i<strArray.length;i++){
      strArray[i] = objArray[i].toString();
      System.out.println(&quot;&quot;+strArray[i]);
}

sorry!!

 

[thekobbler]

Hmm likewise with my initial response..

it should read..

String[] strArray = new String[array.length];
for(int n=0;n<array.length;n++) strArray[n] = (String)array[n];

where array is an Object[] where each element is a String.

NOTE: in future dont type [letter-i] as it will be translated as italic.

 

[toolkit]

You can cast an Object array to a String array. Example code:

public class Test {

  private static String[] s = { "1", "2", "3" };

  public static Object method1() {
    return s;
  }

  public static Object[] method2() {
    return s;
  }

  public static void main(String[] args) {

    String[] s2;
    s2 = (String[]) method1();
    for(int i = 0; i < s2.length; i++)
      System.out.println(i+&quot;: &quot;+s2[i]);
    s2 = (String[]) method2();
    for(int i = 0; i < s2.length; i++)
      System.out.println(i+&quot;: &quot;+s2[i]);
  }
}

Cheers, Neil

 

[thekobbler]

But, the question was catsing an Object[] to a String[], your solution surely doesn't work the other way round.

 

[thekobbler]

To make it clear, Neil, your code doesn't work if the static s is an Object[].

 

[meadandale]

If the Object array IS a String array, yes, you can cast it. If was instantiated as an Object array or an array of some type other than String then, no, you cannot cast it.

 

[toolkit]

Actually, the code does work if static s is an Object[], namely:

  private static Object[] s = new String[] { "1", "2", "3" };

But as meadandale states, this won't work if the Object[] reference does not point to a String[] on the heap. For a truly random array of Objects, you would need to loop through, and call toString on each element in turn. I was just being pedantic in that YES, you can cast an Object[] reference to a String[] reference, so long as the object on the heap is a String[] object. ;-)