Help Understanding Code

janet287

Hi,
I know this is just a small segment of code, so it may be tough to understand without the context. Another programmer worked on this and changed these 3 lines. The logic is excluding a column from displaying on the screen, but I don't understand how it is working.

I need to modify it to exclude a second column, but can't tell how to do that. Can anyone explain to me how this is working and what might need to be changed to exclude a 2nd column?

$columncount1 = $columncount++;
$cellclasses = 'cell c'.$columncount1;
if(!($columncount1 == substr($this->col,1)))

Originally the code looked like this:
$cellclasses = 'cell c'.$columncount++;
and then he changed it as shown above to somehow exclude a column from showing.

So frustrating to not understand. I am sure it is a simple change. Any help would be great! Thanks.

PS - I tried substr($this->col,2) which seemed like the obvious solution but it didn't work...

paulnaj

Hi,

I'll have to make a few assumptions about other parts of the code. From this line ...

$columncount1 = $columncount++;

... I assume that this bit of code is in some kind of loop, cycling through some column data. $columncount1 has probably been initialised to zero (or one), and the above line increments the count within each 'run' of the loop.

In the line ...

if(!($columncount1 == substr($this->col,1)))

... substr($this->col,1) is just stripping the first character off of whatever is stored in $this->col. (For example, if $this->col has value 'a1' then substr($this->col,1) will have value '1')

So, $this->col will be the excluded column since the above line is asking whether the counter is NOT equal to (stripped) value in $this->col.

To get another column excluded, you will have to find out where and how $this->col is defined, and duplicate it's definition ($this->col2, for example). You could possibly also extend $this->col to be an array of 'excluded' columns, but we'll have to know more before being specific.

Hope that helps.

janet287

Hmmm...ok that helps. I think the array of excluded columns would be the better way to go, as there is quite a lot of logic in the if statement follows that, so to duplicate twice would probably be messy.

Can you help me write the array? Assuming I define a $col2 variable above [var $col 2= '';], how would I write the array here?

Any help would be much appreciated. Let me know what other details you need. Just don't want to drown you in the full, long php document.

paulnaj

Hi again,

OK, again I can make another assumption ... the '$this' bit of '$this->col' tells us we are in the definition of a class.

Try to isolate the class ... something like ...

class Blahblah {
   var $soandso = '';
   //... more vars

  function Blahblah(/*...*/){
  }

  //... more functions
}

Then look for ALL instances of where $this->col is used in this class. You'll need to know all of them since changing it to an array will affect these instances as well.

If the whole class is not too big, then post it all up (in php tags for readability).

See how you get on.

janet287

Ok great, here are all the instances. It is actually fairly isolated. Thank you so much for the help.

line 92 :
var $col = '';

line 691 :
if($element['object']->itemname =='Summary Attendance')
{
$this->col = $columnclass;
}
if(!($element['object']->itemname =='Summary Attendance'))
{

line 703 :
}

line 838 :

            $columncount1 = $columncount++;

$cellclasses = 'cell c'.$columncount1;
if(!($columncount1 == substr($this->col,1))){

line 989:
}

line 1202:
if(!(($columncount+2) == substr($this->col,1)))
$avghtml .= '<td class="cell c' . $columncount.'">'.$gradehtml.$numberofgrades.'</td>';
$columncount++;

line 1284:
if(!($columncount == substr($this->col,1)))

paulnaj

Hmm, odd ... can't see why whoever wrote the code needed to define '$columncount1' in the first place.

Anyway, still not enough info, I'm afraid. Near line 691 we get ...

$this->col = $columnclass;

... so we're now going to have to find where $columnclass is defined as well, since this will also have to changed into an array.

Also, in your previous post you mentioned the definition 'var $col = "";'. From the instances you picked out, '$this->col' seems to be set only if one condition is satisfied (when $element['object']->itemname equals 'Summary Attendance'), otherwise it will remain an empty string. Does that sound correct?

You might have to give a bit more info about what it is you are exactly trying to do in context of all the other things that are going on.

janet287

This may be way more than you wanted, but I've uploaded the whole file below. Here is the basic idea. The logic here populates a gradebook. But there are 2 columns in the gradebook by default that we don't want there. One is called Course Attendance, which is already working great in the file. The other column is called Attendance and that is the one I am trying to add. You'll see some of my feeble attempts if you look at the line numbers I mentioned in the last posting.

It would see fairly easy to just modify the logic to exclude the 2nd column, but I am not getting it to work. I get the header part out, but can't seem to get the column itself to remove from the screen - which I believe is controlled by the small segment I originally posted.

Any help would be much appreciated!!

paulnaj

Hi Janet,

Sorry haven't got time at the moment to have more than a quick look, but can you post the up the file before you made any alterations ... there seem to be a few odd lines of code (like the one I mentioned before).

janet287

Thanks. Here is the clean file. If you have a minute to provide any suggestions, I'd appreciate it. I am under some pressure to figure this out. 🙂

paulnaj

Hi Janet,

Had a chance to have a more detailed look but just can't see clearly which variable stores the current column number in the function get_headerhtml().

If we knew which, then would simply store this value in an array (could just change var $col = '' to var $col = array(); to set this up) when we hit 'Summary Attendance' and and when we hit 'Attendance' whilst in the function get_headerhtml().

Then, when we are the function get_studentshtml(), we could merely test whether the current column is in this array().

$columncount seems to be a candidate, but it is potentially incremented so many times within a single loop (using the ++ format), that is not clear at all what this actually represents.

However, you could do a test on the basis that $columncount IS the right one.

I've attached a modified file ... the crucial lines are 62, 607-616 and 725-873. In the last chunk, all the real changes is in the line 727 - all the rest is just indented code.

If it works, we've been lucky. If not, maybe it'll help you to find the right variable anyway.

Cheers
P

EDIT: forgot to attach the file - it's there now!

janet287

thanks so much. I'll take a look and see what I can come up with.

cyberlew15

its checking boolean logic as in true or false on a value to make it simple basically your old code just added cells without any logic the new code checks the next column then it checks if columncount1 or the column after this one doesn't equal the second character in the current column. the only way I can see this being useful is in a spreadsheet also this person seems to be a bad coder why not change the code again to

$cellclasses = 'cell c'.$columncount++;
if($columncount++ != substr($this->col,1))

this is checking for false values which should be the best way and save alot of time re-writing otherwise use this code

$cellclasses = 'cell c'.$columncount++;
if($columncount++ == substr($this->col,1)){}
else

its still three lines and wont require a massive rewrite of your code

Hope that helps