RE: [PHP] Generate every possible combination

2002-05-16 Thread Lance Lovette 

Here's the function I use:

// array array_permute(array [, string])
//
// Returns an array containing the permutations of the values in an array.
//
// Example:
// $a = array(1, 2, 3);
// $p = array_permute($a)
//
// Result:
// p[0] = '1,2,3'
// p[1] = '1,3,2'
// p[2] = '2,1,3'
// p[3] = '2,3,1'
// p[4] = '3,2,1'
// p[5] = '3,1,2'
//
function array_permute($a, $glue = ',')
{
$retval = array();
array_permute_internal($a, $glue, $retval, 0, count($a));
return $retval;
}

// Private function used by array_permute.
function array_permute_internal($a, $glue, $retval, $depth, $ubound)
{
if ($ubound  0)
{
for ($i=0; $i  $ubound; $i++)
{
$c = $a[$depth+$i];
$a[$depth+$i] = $a[$depth];
$a[$depth] = $c;
array_permute_internal($a, $glue, $retval, $depth+1, 
$ubound-1);
$c = $a[$depth+$i];
$a[$depth+$i] = $a[$depth];
$a[$depth] = $c;
}
}
else
{
$retval[] = implode($glue, $a);
}
}

-Original Message-
From: Evan Nemerson [mailto:[EMAIL PROTECTED]]
Sent: Thursday, May 16, 2002 12:17 AM
To: [EMAIL PROTECTED]
Subject: [PHP] Generate every possible combination


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



--
Think not those faithful who praise all thy words and actions, but those who
kindly reprove thy faults.

Socrates


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[PHP] Generate every possible combination

2002-05-15 Thread Evan Nemerson 

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



-- 
Think not those faithful who praise all thy words and actions, but those who 
kindly reprove thy faults.

Socrates


-- 
PHP General Mailing List (http://www.php.net/)
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RE: [PHP] Generate every possible combination

2002-05-15 Thread Martin Towell 

recursive function, passing back in the array, minus the current position
and current combination. when array is empty, use current combination.

um... something like (but not tested)

function comby($arr, $comb = )
{
  $num = count($arr);
  if ($num == 0)
  {
echo $comb;
return;
  }

  for ($i = 0; $i  $num; $i++)
  {
$tmp_comb = $comb . $arr[$i];
$tmp_arr = $arr;
array_splice($arr, $i, 1);
comby($tmp_arr, $comb);
  }
}

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

-Original Message-
From: Evan Nemerson [mailto:[EMAIL PROTECTED]]
Sent: Thursday, May 16, 2002 2:17 PM
To: [EMAIL PROTECTED]
Subject: [PHP] Generate every possible combination


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



-- 
Think not those faithful who praise all thy words and actions, but those who

kindly reprove thy faults.

Socrates


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PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php

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