PHP Advanced Array looping concept for comparision

Question

I have a array like following...

array(2) {
  ["gender"]=>
   array(2) {
    [1]=>
    string(4) "Male"
    [2]=>
    string(6) "Female"
  }
  ["agegroup"]=>
  array(3) {
    [3]=>
    string(7) "18 - 24"
    [4]=>
    string(7) "25 - 40"
    [5]=>
    string(7) "40 - 65"
  }
}

This array is dynamic. As like 'gender' and 'age group' there can be any number of items. all these items are sub arrays (associative). I want to write a loop in php which loops from first array element against each in further array elements.

In the above example... the following output should come...
Male- 18-24
Male- 25-40
Male- 40-65

FeMale- 18-24
FeMale- 25-40
FeMale- 40-65

If array is like following...

array(2) {
  ["location"]=>
   array(2) {
    [A]=>
    string(4) "New York"
    [B]=>
    string(6) "London"
  }
  ["gender"]=>
   array(2) {
    [1]=>
    string(4) "Male"
    [2]=>
    string(6) "Female"
  }
  ["agegroup"]=>
  array(3) {
    [3]=>
    string(7) "18 - 24"
    [4]=>
    string(7) "25 - 40"
    [5]=>
    string(7) "40 - 65"
  }
}

then... output should be...

New York- Male- 18-24
New York- Male- 25-40
New York- Male- 40-65

New York- FeMale- 18-24
New York- FeMale- 25-40
New York- FeMale- 40-65

London- Male- 18-24
London- Male- 25-40
London- Male- 40-65

London- FeMale- 18-24
London- FeMale- 25-40
London- FeMale- 40-65

If the array length is defined I will be able to use foreach() to write snippet. But the array length of both parent and sub array is dynamic... can some one give me a hint of how to loop it to get the desired output ?

The keyword you're looking for is "cartesian product", and there have been [lots](http://stackoverflow.com/questions/6311779/finding-cartesian-product-with-php-associative-arrays), [and](http://stackoverflow.com/questions/2516599/php-2d-array-output-all-combinations) [lots](http://stackoverflow.com/questions/4549794/how-to-find-every-possible-combination-of-arrays-in-php) of [questions](http://stackoverflow.com/search?q=%5Bphp%5D+cartesian+product) asking for the same over time. — salathe, Jun 22 '15 at 20:03
@salathe Realy, duplicate. But too complex solutions are there :) — splash58, Jun 22 '15 at 20:12

splash58 · Accepted Answer · 2015-06-24T11:34:32.353

3

function make ($arr, $pref = '') {            // pref - saving path to this point
 foreach (array_shift($arr) as $item)         // take the 1st item of array and remove it
   if($arr) make($arr,$pref . $item ." - ");  // Call with sub-tree, add item to path
   else echo $pref . $item ."\n";             // Empty array - we are at leaf
}

make($arr);

for 2nd case result:

New York - Male - 18 - 24
New York - Male - 25 - 40
New York - Male - 40 - 65
New York - Female - 18 - 24
New York - Female - 25 - 40
New York - Female - 40 - 65
London - Male - 18 - 24
London - Male - 25 - 40
London - Male - 40 - 65
London - Female - 18 - 24
London - Female - 25 - 40
London - Female - 40 - 65

edited Jun 24 '15 at 11:34

answered Jun 22 '15 at 19:50

splash58

26,043
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The OP barely understands loops, so you give them recursion? – PiranhaGeorge Jun 22 '15 at 19:55
1

There will come time when he has to understand recursion, why not now ? – viral Jun 22 '15 at 19:56
he writes about diff amount of levels – splash58 Jun 22 '15 at 19:57
@Viral because most people learn to walk before they run. Plus iteration is nearly always faster than recursion. – PiranhaGeorge Jun 22 '15 at 20:01
@splash58 sorry, my bad. I misread the question. – PiranhaGeorge Jun 22 '15 at 20:08
@PiranhaGeorge no problem :) – splash58 Jun 22 '15 at 20:09
@splash58 thank you very much... it worked perfect :) – user2301765 Jun 24 '15 at 08:37
Glad to help. You are welcome – splash58 Jun 24 '15 at 08:46
@splash58 - the code is working perfect. can you explain it a little bit ? i was trying to make a final array of all combinations (each combination as a array value). but could not able to figure out as it calls again and again same function recursively... – user2301765 Jun 24 '15 at 11:26
user2301765 i added comment to code. if it is not enough, write needed output, i try to do it – splash58 Jun 24 '15 at 11:35
thank you very much :) i actually wanted to build final array like this... array('1' => array('New York' ,'Male', '18 - 24'), '2' =>array('New York' ,'Male', '25 - 40'), '2' =>array('New York' ,'Male', '40 - 65')) – user2301765 Jun 26 '15 at 04:10
1

https://eval.in/387925 – splash58 Jun 26 '15 at 05:48
@splash58 - you are amazing... – user2301765 Jun 26 '15 at 05:55

PHP Advanced Array looping concept for comparision

1 Answers1