PHP array_splice

1.函数的作用：数组中元素的删除和替代

2.函数的参数：

　　@params array  &$array

　　@params int      $offset

　　@params int      $length

　　@params array  $replacement_array

3.例子：

 <?php
 /**
  * http://php.net/manual/zh/function.array-splice.php
  *
  * @param $input
  * @param $offset
  * @param null $length
  * @param string $splice
  * @return string
  */
 function str_splice($input, $offset, $length=null, $splice='')
 {
     $input = (string)$input;
     $splice = (string)$splice;
     $count = strlen($input);

     // Offset handling (negative values measure from end of string)
     if ($offset<0) $offset = $count + $offset;

     // Length handling (positive values measure from $offset; negative, from end of string; omitted = end of string)
     if (is_null($length)) $length = $count;
     elseif ($length < 0)  $length = $count-$offset+$length;

     // Do the splice
     return substr($input, 0, $offset) . $splice . substr($input, $offset+$length);
 }

 $string = "The fox jumped over the lazy dog.";

 // Outputs "The quick brown fox jumped over the lazy dog."
 echo str_splice($string, 4, 0, "quick brown ");