[PHP] Re: Generate every possible combination

2002-05-16 Thread Martin Wickman 

Evan Nemerson wrote:
 I need to generate every possible combination of the the values in an array. 
 For example, if...
 
 $array = Array(A, B, C);
 I really have no idea where to begin. The best lead I can think of is that 
 there are going to be n! elements in the output array, where n is the size of 
 the input array.

Correct, this also implies that using more than say 20 elements (20!) 
will take *loads* of CPU time and memory. Anyway, I did such a program 
once to test the performance of VB versus Java but alas I dont keep it 
around. It was recursive tho.

A quick check on google came up with some code here:

http://www.delphiforfun.org/Programs/Permutes_1.htm

and som theory here:

http://www.theory-of-evolution.org/Main/chap4/permutations_7.htm


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[PHP] Re: Generate every possible combination

2002-05-15 Thread Austin Marshall 

Evan Nemerson wrote:
 I need to generate every possible combination of the the values in an array. 
 For example, if...
 
 $array = Array(A, B, C);
 
 I want to be able to do something like
 
 print_r(magic_function($array));
 
 which would output
 
 Array
 (
   [0] = ABC
   [1] = ACB
   [2] = BAC
   [3] = BCA
   [4] = CAB
   [5] = CBA
 )
 
 I really have no idea where to begin. The best lead I can think of is that 
 there are going to be n! elements in the output array, where n is the size of 
 the input array.
 
 Any help would be greatly appreciated.
 
 
 Evan
 
 
 

for ($x=ord(A);$x=ord(Z);$x++)
{ for($y=ord(A);$y=ord(Z);$y++)
   { for($z=ord(A);$z=ord(Z);$z++)
 { $array[]=chr($x).chr($y).char($z);
 }
   }
}

is a quick suggestion.  Haven't tested it.



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[PHP] Re: Generate every possible combination

2002-05-15 Thread Austin Marshall 

Austin Marshall wrote:
 Evan Nemerson wrote:
 
 I need to generate every possible combination of the the values in an 
 array. For example, if...

 $array = Array(A, B, C);

 I want to be able to do something like

 print_r(magic_function($array));

 which would output

 Array
 (
 [0] = ABC
 [1] = ACB
 [2] = BAC
 [3] = BCA
 [4] = CAB
 [5] = CBA
 )

 I really have no idea where to begin. The best lead I can think of is 
 that there are going to be n! elements in the output array, where n is 
 the size of the input array.

 Any help would be greatly appreciated.


 Evan



 
 for ($x=ord(A);$x=ord(Z);$x++)
 { for($y=ord(A);$y=ord(Z);$y++)
   { for($z=ord(A);$z=ord(Z);$z++)
 { $array[]=chr($x).chr($y).char($z);
 }
   }
 }
 
 is a quick suggestion.  Haven't tested it.
 
 

never mind, wasn't paying attention.


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