text file read

[davissj]

I am trying to read a cgi/perl generated textfile (.dat) and display the 4 most recent rows of data. It looks like this:

id|evt_label|evt_start_date|evt_length|evt_details|evt_organization_id|evt_attributes|evt_icon|timestamp|
0|4th+of+July|7/4/2002|1|%0a|1||us_flag|1010452776|
1|Christmas|12/25/2002|1|%0a|1||exclamation|1010452857|
2|New+Years+Day|1/1/2002|1|%0a|1||exclamation|1010453120|
3|Mothers+Day|5/12/2002|1|%0a|1||exclamation|1010454791|

As you can see it is delimited by | but I would like to 4 most recent based on the evt_start_date field compared to the current date. I am using a ready made application otherwise I would use mySQL which I know better. How can I accomplish this? Please help!

[zenon]

My suggestion:

$fd = fopen("ciccio.dat","r");
while (!feof ($fd)) {
    $buffer = fgets($fd, 4096);
	preg_match("|\\|[0-9]/[0-9]/[0-9]\\||",$buffer,$arr);
	echo $arr[0]."<br>";
}
fclose ($fd);

$arr[0] will return |07/02/2002| for example

[the_Igel]

$strings = file('data.dat');

foreach($strings as $string)
$array[] = split('|', $string);

now you have 2d-array $array, containing all the records in your data.dat .

Then sort it by time descending (using usort(), or maybe there is some easier way) and use first four items.]

Sure this method costs loads of memory, if your file is big enough.

Another way is like this

foreach ($strings as $string)
{
$tmp = 0;
foreach($array as $record)
   if ($string[2] < $record[2])  $tmp = 1;   //boolean var to check if $string is older than all the records in $array
if (!tmp or (count($array) < 4))
  {// here to be some code that replace oldest record in $array with $string.
   // you can try to write it yourself :)
  }
}

Here we never keep $array longer than 4 records, but the code becomes more complicated.