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 ");