Combinations !

[junelis]

Hi friends can someone tall me how to make code who will calculate all combinations from one array.

 

example : array(2, 5, 7, 3, 4, 6)

 

examle: 2, 5, 7

2, 5, 6

2, 5, 3

2, 5, 7, 3

...

if I i want 3/6 should be 20 combinations

if I want 4/6 should be 10 combinations

or 5/6  6 combin.

 

can someone give idea how to make this

 

Thanks !!!

 

[genericnumber1]

I don't quite understand what you want.

 

Count the number of permutations?

it's just n factorial (n! where n is the number of elements)

 

Find all possible permutations? Find a certain number of permutations based upon the number of elements? Based upon certain elements?

That's a bit more complicated, and no point giving you code for one question when you may have another.

 

[Acs]

I think if just looks for the word "permutations" he will already have plenty of code

Sometimes I think that knowing what you want or what to look for is the hardest part in our software world!

[genericnumber1]

I think if just looks for the word "permutations" he will already have plenty of code

Sometimes I think that knowing what you want or what to look for is the hardest part in our software world!

 

for sure

[junelis]

Ok i will give one more examlple:

array(green, fly, blue, dry, small);

from this 5 word I want all combinatitons from by 3 word

we have 3 from 5 that is 10 combinations

1. green, fly, blue

2. green, fly, dry

3. green, fly, small

4. green, blue, dry

5. green, dry, small

6. green, blue, small

7. fly, blue, dry

8. fly, blue, small

9. blue, dry, small

10. fly, dry, small

 

but i can`t make this in code. please if someone know to post it.

 

 

[waynew]

 

http://php.happycodings.com/Algorithms/code21.html

 

http://www.phpclasses.org/browse/package/200.html

 

http://www.webmasterworld.com/forum88/778.htm

[sasa]

try

<?php
function my_permut($a, $num, $start = 0){
if(!is_array($a)) return false;
if (count($a) == $num) return array($a);
if ($num == 1){
	$out = array();
	for ($i = $start; $i < count($a); $i++) $out[]=array($a[$i]);
	return $out;
}
$a = array_values($a);
$out = array();
for ($i = $start; $i <= count($a) - $num; $i++){
	$d = my_permut($a, $num-1, $i+1);
	foreach ($d as $e){
		array_unshift($e,$a[$i]);
		$out[] = $e;
	}
}
return $out;
}

$x = my_permut(array(1,2,3,4,5),3);
print_r($x);
?>

[junelis]

OK i will try this code but i dont think that will be ok  because I want combinations not premutations

in combinations  1. green, fly, blue

                      2. fly, green, blue

are same but not in permitation

once again please help me if you have code for combinations.

Thanks !!!

 

[sasa]

i changed my permutation function but i don't change its name

sorry