php merge associative array with duplicate keys code example

Example 1: php combine 2 arrays keep duplicates

$arrKeys = array('str', 'str', 'otherStr');
$arrVals = array('1.22', '1.99', '5.17');
function foo($key, $val) {
   return array($key=>$val);
}

$arrResult = array_map('foo', $arrKeys, $arrVals);

Example 2: array merge with same key in php

Input : $a1=array("a"=>"raj", "b"=>"striver");
        $a2=array("z"=>"geeks", "b"=>"articles");
Output : 
Array
(
    [a] => raj
    [b] => Array
        (
            [0] => striver
            [1] => articles
        )

    [z] => geeks
)