PHP - How to partially compare elements in 2 arrays

Question

I have 2 arrays:

$arr1 = array('Test', 'Hello', 'World', 'Foo', 'Bar1', 'Bar'); and $arr2 = array('hello', 'Else', 'World', 'Tes', 'foo', 'BaR1', 'Bar'); 

I need to compare 2 arrays and save the position of the corresponding elements in the 3rd array $arr3 = (3, 0, 2, 4, 5, 6); //expected result, displaying position of matching element of $arr1 in $arr2. $arr3 = (3, 0, 2, 4, 5, 6); //expected result, displaying position of matching element of $arr1 in $arr2.

By “matching” I mean all elements that are identical (for example, World) or partially the same (for example, Test and Tes), as well as those elements that are the same but are in another case (for example, Foo and foo, Bar and bar )

I tried a number of combinations and various functions without success, using functions such as array_intersect(), substr_compare(), array_filter() and much more. I am not asking for an exact solution, just something that will help me on the right path, because I have been circling all day.

Answer 1

It seemed to work for me, but I'm sure there are some extreme cases that I am missing, that you will need to check:

 foreach( $arr1 as $i => $val1) { $result = null; // Search the second array for an exact match, if found if( ($found = array_search( $val1, $arr2, true)) !== false) { $result = $found; } else { // Otherwise, see if we can find a case-insensitive matching string where the element from $arr2 is at the 0th location in the one from $arr1 foreach( $arr2 as $j => $val2) { if( stripos( $val1, $val2) === 0) { $result = $j; break; } } } $arr3[$i] = $result; } 

It creates the desired output array :

 Array ( [0] => 3 [1] => 0 [2] => 2 [3] => 4 [4] => 5 [5] => 6 ) 

Answer 2

Try array_uintersect() with a callback function that implements your matching algorithm.

Answer 3

It looks like you need 2 foreach and stripos loops (or mb_stripos for Unicode) for comparison.

Answer 4

I came up with this to account for duplicates. It returns both keys and both values ​​so you can compare them if it works correctly. To clarify this, you can simply comment on lines setting values ​​that you don't need. It matches all cases.

 <?php $arr1 = array('Test', 'Hello', 'World', 'Foo', 'Bar1', 'Bar'); $arr2 = array('hello', 'Else', 'World', 'Tes', 'foo', 'BaR1', 'Bar'); $matches = array(); //setup the var for the initial match $x=0; foreach($arr1 as $key=>$value){ $searchPhrase = '!'.$value.'!i'; //Setup the var for submatching (in case there is more than one) $y=0; foreach($arr2 as $key2=>$value2){ if(preg_match($searchPhrase,$value2)){ $matches[$x][$y]['key1']=$key; $matches[$x][$y]['key2']=$key2; $matches[$x][$y]['arr1']=$value; $matches[$x][$y]['arr2']=$value2; } $y++; } unset($y); $x++; } print_r($matches); ?> 

The result is as follows:

  Array ( [1] => Array ( [0] => Array ( [key1] => 1 [key2] => 0 [arr1] => Hello [arr2] => hello ) ) [2] => Array ( [2] => Array ( [key1] => 2 [key2] => 2 [arr1] => World [arr2] => World ) ) [3] => Array ( [4] => Array ( [key1] => 3 [key2] => 4 [arr1] => Foo [arr2] => foo ) ) [4] => Array ( [5] => Array ( [key1] => 4 [key2] => 5 [arr1] => Bar1 [arr2] => BaR1 ) ) [5] => Array ( [5] => Array ( [key1] => 5 [key2] => 5 [arr1] => Bar [arr2] => BaR1 ) [6] => Array ( [key1] => 5 [key2] => 6 [arr1] => Bar [arr2] => Bar ) ) )