Date Manipulation

[SkippyK]

I am developing an application into which a user will enter a date in dd/mm/yyyy format. I am then presented with two problems.

1) what is the correct way to validate the date the user enters? The field has been defined as type="date" on both the form and database.

2) Once the user has entered a valid date, how do I then reformat the date before populating to the database in yyyy/mm/dd format?

TIA

[Quevas]

The function checkdate(month,day,year), return true or false if a date is or not valid.

To change format:

$date="31/12/2002"; dd/mm/yyyy

$datechanged=$date[7].$date[8].$date[9].$date[10]."/".$date[4].$date[5]."/".$date[1].$date[2];
yyyy/mm/dd

Surely there's an easily way to do that, but even this works.

:p

[PHPdev]

I think that checkdate() will be your friend in this situation. Unfortunatly you do have to break down the date before using this function.

Once the date format has passed the checkdate function, you can use the date() function to reorder the date for the proper format. You may have to do something like date("Y-m-d",stringtodate($var));

Just my .02

PHPdev

[daveyboy]

you can use strtotime() to change a lot of formats into a unix timestamp. then you can mess around with this and turn it back into a date with strftime(). check out the manual for details:

http://de.php.net/manual/en/function.strtotime.php
http://de.php.net/manual/en/function.strftime.php

strtotime() will return -1 if the date is invalid. In situations where you need valid, formatted data, it's a good idea to use selectboxes instead, so the users can only select a valid date.

[SkippyK]

All the above suggestions look reasonable, and thank you very much for reponses.

Unfortunately, I'm still not entirely comfortable with functions, where could I find examples / snippets of any of these in use? I've had a quick look at the snippets on this site, but can't find anything that looks similar.

Thanks again

[PHPdev]

check out www.php.net, they generally have examples

PHPdev

[daveyboy]

I'm building something very similar at the moment, but a lot of the functionality is spread over many, many classes and files, so this is about the only thing i can find which may help rather than confuse you. It returns an HTML selectbox called $name, with the options in array $items.

If you make a few of these, one for year, month and day, with the current date selected, you are guaranteed valid data you can use:

$years = array( '2002' => 2002,
    '2003' => 2002,
    '2004' => 2004,
     etc... );
$months = array( 'Jan' => 1,
    'Feb' => 2,
    etc... );
$days = range(1,31);

$year = get_dropdown( 'year', $years, 2002 );
$mnth = get_dropdown( 'month', $months, 10 );
$day = get_dropdown('day', $days, 13 );


/**
* Generates and returns a pulldown menu for a form.
*
* @access public
* @param string $name
* @param array $items Array of options. Title => value.
* @param string $selected Value of selected item in array $items.
* @return string
*/
function get_dropdown( $name, $items, $selected )
{
	$content = 	"<select name=\"$name\" id=\"$name\">";
	foreach ( $items as $title=>$value ) {
		$content .= "<option value=\"$value\" ";
			if ( $selected == $value ) {
				$content .= 'selected="selected"';
			}
		$content .= ">$title</option>";
	}
	$content .= "</select>";
	return $content;
}

[buck2bcr]

I would use the check date function to check your date. First though I would explode the current date to get the different pieces.

$date = "31/01/2002"; // your format -> dd/mm/yyyy

// make array with your date information
$new_date_array = explode("/",$date);

// put numbers in their own variables
$month = $new_date_array[1];
$day = $new_date_array[0];
$year = $new_date_array[2];

// check and make sure date is valid
$check = checkdate($month,$day,$year);

// if $check returns one, date is valid
if ($check == 1)
{
    $new_date = "$year/$month/$day";
} else
{
    // use whatever you want for error
}

HTH