Development Learning PHP - any advice appreciated

Well I say "learning", but I've been writing basic-ish PHP apps for a while now. The problem I'm getting is that I'm doing something I've never done in PHP and although I've spent a day on Google no-one seems to answer my question.

With other programming languages, when reading from a database, there's usually an exposed property indicating which is the first row, and which is the last row.

I can't seem to find this in PHP, any help?

I've noticed that I could use a for( x to y) loop and check the row number this way but I'm struggling with working out the syntax for this as everything I've read insists on using a while() loop (which is of course the only way I've ever done it before myself).

Thanks

 

I've now got a workaround I'm kinda happy with in place but if anyone does know if there's a built in isfirstrow or islastrow for arrays I'd really like to know!

 

So what was your solution Zoon?

In perl, $#array represents the length of the array @array. So as you iterate through the array you can check if your counter equals the last element of the array, hence $#array.

perl and php are similar so you may be able to use this.

 

PHP:

if ($k == count($array))

where $k is your loop variable. You could use a structure like:

PHP:

while ($k < count($array)) {
   // blah blah
   $k++; 
}

or its for equivalent.

 

I ended up using this:

Code:

$rownum = 1;

while ($row = mysql_fetch_assoc($results))
{

do stuff

$rownum++
}

The most important bit was knowing if its the first row.

I can work out the last by comparing $rownum and mysql_num_rows($results) before doing $rownum++.

Thanks for the suggestion Red Eye but that doesn't seem to be exposed. You can count() your array but you still need to iterate a number through it to know what the current row number is, with the code I'm using.

I'm finding C# and .Net easier for this project but I want people to actually use this stuff and who likes hosting on IIS???

 

It sounds like you're used to getting stuff from a db in an some kind of object with stuff like .movenext or similar?

You can build your own encapsulation, something like the following (thrown together, assuming you're using php4, not tried or tested in any way! it also assumes you give it a proper array, not a hash table):

PHP:

<?php

    class Rowset
    {
        var $rows;
    
        function Rowset($rows)
        {
            $this->rows = $rows;
        }
        
        function moveNext()
        {
            return next($this->rows);
        }
        
        function movePrev()
        {
            return prev($this->rows);
        }
        
        function getRow()
        {
            return current($this->rows);
        }
        
        function reset()
        {
            reset($this->rows);
        }
        
        function isLast()
        {
            return key($this->rows) == sizeof($this->rows)-1;
        }
        
        function isFirst()
        {
            return key($this->rows) == 0;
        }
    }
    
    
    $rows = array('one', 'two', 'three', 'four', 'five');
    
    $res = new Rowset($rows);
    

    do
    {
                if ($res->isFirst()) echo "(we are on the first row!)";
                if ($res->isLast())  echo "(we are on the last row!)";
        echo $res->getRow(), "\n";
    }
    while ($res->moveNext());

That'll output:

Code:

(we are on the first row!) one
two
three
four
(we are on the last row!) five

You'd need to swap:

PHP:

$rows = array('one', 'two', 'three', 'four', 'five');

with

PHP:

// [your other code here]
while($row = mysql_fetch_assoc($results))
{
 $rows[] = $row;
}


to use this in your code

 

That's really useful thanks RTT

Its a shame php just doesn't have an evaluator which would tell you if its the first row or last row.

And yeah that's sort of where I'm coming from. Back in the days of asp you could do recordset.eof

Its been a while since I did any serious development and its always a brain ache dredging up your memories of how things work!

 

Thought so

 

In honesty this problem only exists because I'm hacking an open source product we use at work to do something the original writer never intended.

I am however writing a hopefully superior one myself, so I will design it to avoid this pitfall from the ground up