Create a constant date format in PHP

I was using CI as my framework. How can I set a CONSTANT date format so that I don't need to change and search for date("y-m-d") in all file开发者_如何学C?

I haven't tried exactly what you're asking for, but somewhere you should be able to use the define function to define a constant string matching your format, which you can then reference throughout your app.

Example:

define( 'MY_DATE_FORMAT', "y-m-d" );

$date = date( MY_DATE_FORMAT );

Where you put this in CodeIgniter is a whole other problem. I'll look through the docs and see what I can find.

HTH.

EDIT: Found this forum topic on the CI site: http://codeigniter.com/forums/viewthread/185794/ It should get you started on what you need to do.

Put this is a common header file:

define('my_date_format', 'y-m-d');

To use the constant:

// remember to include the header file first
date(my_date_format);

To format 2010-11-10 10:12:11 to date(m.d.y):

$myDate = new DateTime('2010-11-10 10:12:11');
$myDate->format('m.d.y');

I think when you say "constant" date format you mean you want the same output each time, but you don't literally need a constant in the PHP sense. Just write your own function (or in Codeigniter terms, "helper"):

// Apply your default format to $format
function display_date($timestamp = NULL, $format = 'y-m-d')
{
    // Possibly do some stuff here, like strtotime() conversion
    if (is_string($timestamp)) $timestamp = strtotime($timestamp);

    // Adjust the arguments and do whatever you want!

    // Use the current time as the default
    if ($timestamp === NULL) $timestamp = time();

    return date($format, $timestamp);
}

Example usage:

echo display_date(); // Current time
echo display_date($user->last_login); // Formatted unix time
echo display_date('Next Monday'); // Accept strings

Writing your own function allow much more flexibility in the future.