Need help with the maths on this

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July 2nd, 2009, 06:27 AM

liamdawe

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PHP-General - Need help with the maths on this

Basically each page i have is split up into 7 sections 1 for each post.

Each post has an anchor link on it with "#1, #2" etc. So people can link right to that post.

Which is fine until i get onto a second page. I am not sure how to work out which post to go to in the header redirect.

For example if there are 8 posts there will be two pages right? Page two will only have one post.

How will i go about working that out for each page based on how many posts?

July 2nd, 2009, 06:40 AM

Mark Baker

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PHP Code:


		
			
 $post = 8;

$postPage = floor($post / 7) + 1;

$postNumber = ($post % 7) + 1;

echo $post.' is posting number '.$postNumber.' on page '.$postPage;

Do a search on pagination

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July 2nd, 2009, 06:48 AM

liamdawe

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I honestly don't get what you just posted at all it doesn't seem to be right?

I take it $pageNumber is 7 percent of $post or what?

July 2nd, 2009, 07:05 AM

Mark Baker

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Quote:

Originally Posted by liamdawe

I take it $pageNumber is 7 percent of $post or what?

The % in my code snippet has nothing to do with percentages: it's the modulus operator in PHP.

You obviously haven't actually tried to see what the code snippet does, or tried reading about it in the PHP manual, or tried googling or searching the forums for pagination.

Try doing those things before telling me I'm not right; and then, if I really am not right, try explaining what you want in more detail. I did make one mistake, but the general principle is still correct

PHP Code:


		
			
 $post = 8; 

$postPage = floor(($post -1) / 7) + 1; 

$postNumber = (($post -1) % 7) + 1; 

echo $post.' is posting number '.$postNumber.' on page '.$postPage;

Comments on this post

srisa agrees: Quite a polite reply.

requinix agrees: needs more "politeness"

Last edited by Mark Baker : July 2nd, 2009 at 08:00 AM.

July 2nd, 2009, 07:33 AM

liamdawe

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I tried the code and it simply doesn't work, $postNumber doesn't give me the right value.

Also i don't see how exactly i was supposed to know a percentage symbol didn't mean that, the whole point of me posting here is to get help.

For this code does $post mean the actual post number, or the amount of posts?

July 2nd, 2009, 07:40 AM

srisa

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$post = total number of posts.
$postPage = page number
$postNumber = value that goes into the anchor tag #1, #2 etc.

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July 2nd, 2009, 07:46 AM

liamdawe

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Thought it might be that, altho the postNumber gives no value.

July 2nd, 2009, 07:59 AM

Mark Baker

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PHP Code:


		
			
for ($post = 1; $post < 25; $post++)   {

    $postPage = floor(($post -1) / 7) + 1;

    $postNumber = (($post -1) % 7) + 1;

    echo $post.' is posting number #'.$postNumber.' on page '.$postPage.'<br />';

}

gives

Code:

1 is posting number #1 on page 1
2 is posting number #2 on page 1
3 is posting number #3 on page 1
4 is posting number #4 on page 1
5 is posting number #5 on page 1
6 is posting number #6 on page 1
7 is posting number #7 on page 1
8 is posting number #1 on page 2
9 is posting number #2 on page 2
10 is posting number #3 on page 2
11 is posting number #4 on page 2
12 is posting number #5 on page 2
13 is posting number #6 on page 2
14 is posting number #7 on page 2
15 is posting number #1 on page 3
16 is posting number #2 on page 3
17 is posting number #3 on page 3
18 is posting number #4 on page 3
19 is posting number #5 on page 3
20 is posting number #6 on page 3
21 is posting number #7 on page 3
22 is posting number #1 on page 4
23 is posting number #2 on page 4
24 is posting number #3 on page 4

July 2nd, 2009, 08:06 AM

liamdawe

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That is strange i currently have this:

PHP Code:


		
			
// if we have less than 7 replies its simple

        if ($post_count <= 7)

        {

            // it will be the first page

            $postPage = 1;

            

            // if we have no replies yet then the postcount is 2 (topic + this post)

            if ($post_count == 0)

            {

                $postNumber = 2;

            }



            // unless we already have a reply then it is 2 + this one (topic and first post (which is 2) + this one)

            else

            {

                $postNumber = $post_count + 2;

            }

        }



        // now if the reply count is bigger than 7 then we have more than one page, a little more tricky

        if ($post_count > 7)

        {

            // find out the page we are on first

            $rows_per_page = 7;



            $actual_posts_count = $post_count + 2;



            $postPage = floor($actual_posts_count / $rows_per_page) + 1; 

            $postNumber = (($actual_posts_count -1) % $rows_per_page) + 1;  

        }







        header("Location: viewtopic.php?tid={$topic}&pageno={$postPage}#post{$postNumber}");

Where $post_count is set via the replies field in the database table.

It seems to go up until 9 then go to a second page, and then go to #3 this is strange.

Last edited by liamdawe : July 2nd, 2009 at 08:13 AM.

#10

July 2nd, 2009, 12:47 PM

srisa

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Try this.

php Code:

Original - php Code
$rows_per_page = 7; $actual_posts_count = $post_count + 2; $postPage = floor(($actual_posts_count-1) / $rows_per_page) + 1; $postNumber = (($actual_posts_count -1) % $rows_per_page) + 1; header("Location: viewtopic.php?tid={$topic}&pageno={$postPage}#post{$postNumber}");

 
        $rows_per_page = 7;
        $actual_posts_count = $post_count + 2;
        $postPage = floor(($actual_posts_count-1) / $rows_per_page) + 1; 
        $postNumber = (($actual_posts_count -1) % $rows_per_page) + 1;  
 
        header("Location: viewtopic.php?tid={$topic}&pageno={$postPage}#post{$postNumber}");

#11

July 2nd, 2009, 04:05 PM

alleyOOPs

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in just the pure number of hours you will be spending on little items like this over the next few months I highly suggest buying a book on php/mysql.

I personally think a great starter is the book by ullman and it handles things like pagination (which is what you are trying to do).

It may seem rude, but meant in jest.....RTFM or buy a good starter book. It will save you hundreds of wasted hours.

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