<?php
  /*
  * @author ri7nz <ri7nz.labs@gmail.com>
  */
  function toAttributes($arr){

      $arr = array_map(

              function($value, $key){
                return $key.'="'.$value.'"';
              },

              array_values($arr),
              array_keys($arr)
      );

      return implode(' ', $arr);
  }



  $attr = array(
        'id' => 'input1',
        'class' => 'form-control',
        'name' => 'input1'
  );

  $attr = toAttributes($attr);

  echo "<input type='text' ${attr} />";