PHP Combine 2 matrizes mantêm duplicatas

$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);
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