[haXe] Deep Copy of an array? how can it be done generically

[Franco Ponticelli]

Version 2. This should be a little more faster because uses the native
copy() method of Array (I don't really know if that makes any difference).

class ArrayUtil
{
    static public function main() {
        var test : Array<Array<Int>> = [[0,1,2],[3,4,5]];
        var copyA = test.copy();
        var copyB = deepCopy(test);

        test[1][0] = 100;

        for(i in 0...copyA.length)
            for(j in 0...copyA[i].length)
                trace(copyA[i][j]);

        for(i in 0...copyB.length)
            for(j in 0...copyB[i].length)
                trace(copyB[i][j]);
    }
    /**
    * Does a deep copy on the array, assuming the items are
    * further arrays or have "copy" semantics (such as fundamentals)
    */
    static public function deepCopy<T>( arr : Array<T> ) : Array<T>
    {

        if(arr.length > 0 && Std.is(arr[0], Array)){
            var r = new Array<T>();
            for( i in 0...arr.length ) {
                r.push(cast deepCopy(untyped arr[i]));
            }
            return r;
        } else {
            return arr.copy();
        }
    }
}

On 4/22/07, Franco Ponticelli <franco.ponticelli at gmail.com> wrote:
>
> Does this help?
>
> class ArrayUtil
> {
>     static public function main() {
>         var test : Array<Array<Int>> = [[0,1,2],[3,4,5]];
>         var copy = deepCopy(test);
>         for(i in 0...copy.length)
>             for(j in 0...copy[i].length)
>                 trace(copy[i][j]);
>     }
>     /**
>     * Does a deep copy on the array, assuming the items are
>     * further arrays or have "copy" semantics (such as fundamentals)
>     */
>     static public function deepCopy<T>( arr : Array<T> ) : Array<T>
>     {
>         var r = new Array<T>();
>         for( i in 0...arr.length )
>             r.push(copy(arr[i]));
>         return r;
>     }
>
>     static private function copy<T>( value : Dynamic) : T {
>         if( Std.is( value, Array ) )
>             return cast deepCopy( value );
>         else
>             return value;
>     }
> }
>
> Of course, if you are not copying arrays of primitives you will have to
> call some copy/clone method ...
>
> On 4/22/07, edA-qa mort-ora-y <eda-qa at disemia.com> wrote:
>
> > I often used Matrix like constructs such as:
> >         Array<Array<Int>>
> > The problem is that I don't have an easy way to produce a copy of these
> > structures.  A simple "copy" will just reuse the second level objects,
> > but I want a proper deep copy.
> >
> > Obviously it is easy enough for a given case to do a copy, but I would
> > like to have some kind of generic function which can do the copy,
> > otherwise I'm forced to write a copy operation for every matrix like
> > type that I have.
> >
> > I tried to get something like the following possible, but I always get
> > some kind of compilation error that I can't figure out how to get rid
> > of.
> >
> >
> > class ArrayUtil<T>
> > {
> >         /**
> >          * Does a deep copy on the array, assuming the items are
> >          * further arrays or have "copy" semantics (such as
> > fundamentals)
> >          */
> >         static public function deepCopy( arr : Array< ArrayUtil.T> ) :
> > Array<ArrayUtil.T>
> >         {
> >                 var r = new Array<ArrayUtil.T>();
> >                 for( i in 0...arr.length )
> >                 {
> >                         if( Std.is ( arr[i], Array ) )   //How to do
> > this line?!
> >                                 r.push( deepCopy( arr[i] ) );
> >                         else
> >                                 r.push( arr[i].copy() );
> >                 }
> >
> >                 return r;
> >         }
> > }
> >
> > --
> > edA-qa mort-ora-y
> > Idea Architect
> > http://disemia.com/
> >
> > Sign: Please digitally sign your emails.
> > Encrypt: I'm also happy to receive encrypted mail.
> >
> >
> > --
> > haXe - an open source web programming language
> > http://haxe.org
> >
> >
>
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