Codeigniter在if语句中替换$ _POST

If I have an if statement currently using $_POST what would be the best way to do this using $this->input->post();?

Example:

if($_POST)
{
  Do This

}

According to the docs,

$this->input->post('value')

returns the value or false if it doesn't exist, so you should use this:

if ($this->input->post('value'))
{
    // 'value' can be safely used now, because we know it's there
}