An algorithm for combining two-dimensional array elements

$arr = Array ('    a ', ' B ', ' C '), Array (' C ', ' F '), Array ('    g ', ' Z '), array (    ' x ', ' Y '));//$ Arr subset element length may be more//$arr subset element with $arr other subset element 22 combination or 3344 combination//subset array (' A ', ' B ', ' C ') element does not need combination//22 combination $newarr = Array (  Array (' A ', ' C '), Array (' A ', ' F '), array (' B ', ' C '), Array (' B ', ' F '), Array (' C  ',  ' C '),  array (' C ', ' F '),  ...) 33 Combination $newarr = Array (  array (' A ', ' C ', ' G '),  array (' A ', ' f ', ' G '),  array (' B ', ' C ', ' G '),  array (' B ' , ' f ', ' G '),  array (' C ', ' C ', ' G '),  array (' C ', ' f ', ' G '),  ...) 44 Combination $newarr = Array (  array (' A ', ' C ', ' g ', ' X '),  array (' A ', ' f ', ' g ', ' X '),  array (' B ', ' C ', ' g ', ' X '),  Array (' B ', ' F ', ' g ', ' X '),  array (' C ', ' C ', ' g ', ' X '),  array (' C ', ' f ', ' g ', ' X '),  ...)

Can it be implemented with a function?

$arr: Original Array, $cNum: Combined length function getcombination ($arr, $cNum) {  ...}

Reply to discussion (solution)

You rub together a combination (n takes M's combination) and a Descartes (Cartesian product) function.
In fact, there is no need to write a function, write a rather lost universality

I was thinking first of all, to take an array of length, and then to ask for Cartesian product
First, the recursive, then the product, the final merge array?

If this is the case, then

function Getcombination ($arr, $cNum) {   $res = array ();   foreach (Combination ($arr, $cNum) as $item) {      $res = Array_merge ($res, Descartes ($item));   }   return $res;}

You can do it.

The possible notation for two functions is

function combination ($arr, $num =0) {$arr = Array_values ($arr), $len = count ($arr), if ($num <= 0 | | $num > $len) $num = $len; $res = Array (); for ($i =1, $n =pow (2, $len); $i < $n; + + $i) {$tmp = Str_pad (Base_convert ($i, 2), $len, ' 0 ', STR_PA D_left); $t = Array (); for ($j =0; $j < $len; + + $j) {if ($tmp {$j} = = ' 1 ') {$t [] = $arr [$j];}} if (count ($t) = = $num) $res [] = $t;} return $res;} function Descartes ($d) {$r = Array_pop ($d), while ($d) {$t = array (), $s = Array_pop ($d), if (! Is_array ($s)) $s = array ($s); fo Reach ($s as $x) {foreach ($r as $y) $t [] = Array_merge (Array ($x), Is_array ($y), $y: Array ($y));} $r = $t;} return $r;}

Common algorithms should be written as functions to form a code base. Call when you need to, don't write every time

Common algorithms should be written as functions to form a code base. Call when you need to, don't write every time

Thank you moderator, sleep, immediately read your writing, study and study

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