Simple looping question

[thz_new_york]

I am new to PHP and need some help with some simple looping logic.

I am reading the following data into an associative array and then looping through. I tried to use the next(array) function but this did not seem to work.

I need to find each of the first occurrence of 'L' and the next record where it is not an 'L' to calculate the sum total of date differences e.g. the first would be L=03-01-2001 and A=04-01-2001, and the next would be L= 06-01-2001 and A=09-01-2001.

A 01-01-2001
A 02-01-2001
L 03-01-2001
A 04-01-2001
A 05-01-2001
L 06-01-2001
L 07-01-2001
L 08-01-2001
A 09-01-2001
A 10-01-2001
A 11-01-2001

[CoderDan]

i think something like this (tested it now, this is working 😛)

<?php
$data = <<<DATADUMP
A 01-01-2001
A 02-01-2001
L 03-01-2001
A 04-01-2001
A 05-01-2001
L 06-01-2001
L 07-01-2001
L 08-01-2001
A 09-01-2001
A 10-01-2001
A 11-01-2001
DATADUMP;

$data_array = explode( "\n", $data );

$l_data = false;

foreach ( $data_array as $row )
{
	if ( $data = sscanf( $row, '%s %d-%d-%d' ) )
	{
		if ( $l_data )
		{
			if ( $data[0] == 'A' )
			{
				// current $data is a data
				// calculate your difference vs $l_data
				print_r( $l_data );
				print_r( $data );
				$l_data = false;
			}
		}
		else if ( $data[0] == 'L' )
		{
			$l_data = $data;
		}
	}
}
?>

[thz_new_york]

Thanks for your help on this. I tested and it works also.

How does the actual code for the difference in date values look if they are in separate array elements, would you use an implode?

Also, is there a way to wrap this into a function so that I can apply it over an array based on a select from a database, so that I just get the sum total of days difference?

[CoderDan]

well, to get the difference you're probably best to use mktime on the parts (or make the sscanf into something that gets just the leter and the date string, then strtotime it) and then you can get the difference in seconds, which you can later convert out to days by dividing it by the number of seconds in a day.
I don't see why it couldn't be functionalised, what would the input be?

[thz_new_york]

The input would be an associative array based on a fetch from a database.

Or, is there a simpler way to do this at the database level i.e. MySQL?

Thanks for your help.

[CoderDan]

Well. do you plan to have 1 query, and process all teh differences within it's results, and total them up? in that case, why a function? or do you plan to have a set of queries, and for each query do that? in that case, you could put the function anywhere you like around it. probably easiest to functionalise the entire thing and just pass argument(s) needed to calculate the sql filter.