Reversing an Array's order with PHP3

[Anon]

I got a response to a similair post earlier, but I was really confused by it. I'm still a newbie to PHP, so I kind of need every last detail of the response explained.. anyway, here it goes..

I have a file in which I need to take the contents, reverse the order (right now, the latest addition is at the bottom of the file), and write those to another file. Here is the code...

	/* GENERATE HEADLINES */
	$dafiledirectory = "$dir/$fanfictionindex";

	if($dafilehandle = fopen($dafiledirectory, "r"))

	{

	    while(!feof($dafilehandle))

	    	{
	    	    $dafilecontents[] = fgets($dafilehandle, 255);
		}

		$dasize = count($dafilecontents);
		$dasize = $dasize++;

	for($m=1; $m <= $dasize; $m++) {
		list(
		$headlinesauthor[$m], 
		$headlinestitle[$m], 
		$headlinesdate1[$m], 
		$headlinestime1[$m]
		) = split( '[|]', $dafilecontents[$m] );
	}

	}
	fclose($dafilehandle);

	$headlinesfiledirectory = "$dir/ffheadlines.shtml";

	if($headlinesfilehandle = fopen($headlinesfiledirectory, "w")) {

		$headlinessize = count($headlinesauthor);

		flock($headlinesfilehandle, 2);

		for($h=1; $h < $headlinessize; $h++) {
			fputs($headlinesfilehandle, "\n<LI><A OnMouseOver=\"window.status='Written by $headlinesauthor[$h]'; return-true;\" HREF=\"/resources/fanfiction/display.php?action=viewfanfic&id=$h&title=$headlinestitle[$h]&author=$headlinesauthor[$h]\">$headlinestitle[$h]</A></LI>");
		}

		flock($headlinesfilehandle, 3);

	}
	fclose($headlinesfilehandle);
	/* GENERATE HEADLINES */

That script currently works, but you see, it puts the newest additions LAST, and I need them first. Can someone please explain to me how to do this, thanks.

[Anon]

Instead of reversing your array, why not start at the end of it and work your way to the beginning as you output.

so instead of:

for($h=1; $h < $headlinessize; $h++)

which starts at element 1 and goes through to the last element. use:

for($h=$headlinessize-1; $h > 0; $h--)

[terje-s]

There are tons of different ways to solve this problem. To be very honest with you, I didn't bother to read the php-code 😉 I'll try to give an explenation of the two "most normal" techniques.. (at least in my world they are)

1)
- Open a new file for writing, put the new entry in it
- Open the old file for reading
- read all data from this file and write it to the first one
- close both files
- delete the old file
- rename the new file to its appropriate name

2)
- Add the new entry to the first index of an array
- Open the old file for reading
- read all the data in it to the same array
- close the file, and reopen for writing
- write each index of the array to file
- close file

example 1:

/ open "new.txt" for writing /
$outfp = fopen("new.txt", "w");

/ open "old.txt" for reading /
$infp = fopen("old.txt", "r");

/ output new entry to "new.txt" /
fputs($outfp, "new entry");

/ concatenate with old data /
while ($oneLine = fgets($infp, 4096))
fputs($outfp, $oneLine);

/ close file pointers /
fclose($infp);
fclose($outfp);

/ remove old file, and rename the new one /
unlink("old.txt");
rename("new.txt", "old.txt");

example 2:
$fileData = array();
$fileData[] = "new entry";

/ open file for reading /
$infp = fopen("old.txt", "r");

/ read old file data to array /
while ($fileData[] = fgets($infp, 4096));

/ close file pointer /
fclose($infp);

/ reopen file for writing /
$outfp = fopen("old.txt", "w");

/ dump array to file /
for ($x = 0; $x < count($fileData); $x++)
fputs($outfp, $fileData[$x]);

/ close file pointer /
fclose($outfp);

[Anon]

Thanks PeeJ, it worked flawlessly!