[RESOLVED] Iterating through my array

j0hn_

I have a piece of code that parses my xml file (which contains the filenames and categories of a bunch of images) into a multidimensional array.

I have a thumbnail gallery (detail.php) and when you click on a thumbnail it goes to another page that displays the full size image. The link looks like this =>

http://www.mydomain.com/image.php?article=boxbody1.

It's actually a link written on the fly contained within a 'for loop' like this =>

echo " <a href=";
echo "image.php?article=";
echo $person_data[$i]["imagetype"];
echo $x;

"imagetype" is a tag parsed from my xml file and $x increments everytime.

Just below my parser in image.php I have the following =>

$displayPic = "$article" . ".jpg";

and then further down where I want the image displayed I'm using the following line to display the image=>

I want to be able to navigate to the first,last, next and previous images which are really just values in my array.

My lecturer in college told me that I would end up with a piece of code similar to the following for each link =>

<?php
echo "<td class=bgwhite align=center height=52>";
echo "<a href=";
echo "imagenav.php?article=";
echo $firstOne;
echo "&mytype=";
echo $myType;
echo ">first</a></td>";
?>

The reason for the $myType variable is that when the xml file is parsed and read into the array, all of the values for imagetype are read in and we only need images of a particular type.

I will be using $firstOne, $lastOne, $prevOne and $nextOne as my variables. I remember my lexturer saying that I needed to use the 'array_values' function to return all the values in the array and that I would need to use the 'unset' function before adding or subtracting the value of the variable.

I know this is similar to the pagination technique documented here on this site but my problem really lies in iterating through my array.

Can someone please help, as my lecturer is on sick leave and I have nobody else to bounce these ideas off. Thank you.

laserlight

I am not sure what exactly you need in this case, but you could take a look at the [man]prev/man, [man]next/man, [man]end/man and [man]reset/man functions.

j0hn_

I kinda was told not to use those functions by my lecturer, i don't know why, i suggested using them myself...

laserlight

I kinda was told not to use those functions by my guru of a lecturer, i don't know why, i suggested using them myself...

Because you are not allowed to use them, or...?

j0hn_

No nothing like that, he had some good reason, I just can't remember what it was.

laserlight

hmm... I read your description again, and yes, it does look like those functions may not be what you want.

Basically, you have an array containing the image names on the thumbnail page, and on the image page you want to link to the first, last, next and previous images when displaying the current image.

How do you want to pass the array information to the image page?

j0hn_

Well I'm not sure if I'm making sense but here goes...I have my parser code at the top of both pages and there is a seperate xml file for each i.e. thumbs.xml & images.xml. So the array on the image page is created by the parser code on that page.

The parser look like this =>

<?php
if( ! ($fp = fopen( "./images/images.xml" , "r" )) )
die("Couldn't open xml file!");
$person_counter = 0;
$person_data = array();
$xml_current_tag_state = '';
function startElementHandler( $parser, $element_name, $element_attribs )
{
global $person_counter;
global $person_data;
global $xml_current_tag_state;
if( $element_name == "ITEM" )
{
$person_data[$person_counter]["author"] = $element_attribs["AUTHOR"];
}
else
{
$xml_current_tag_state = $element_name;
}
}
function endElementHandler( $parser, $element_name )
{
global $person_counter;
global $person_data;
global $xml_current_tag_state;
$xml_current_tag_state = '';
if( $element_name == "ITEM" )
{
$person_counter++;
}
}
function characterDataHandler( $parser , $data )
{
global $person_counter;
global $person_data;
global $xml_current_tag_state;
if( $xml_current_tag_state == '' )
return;
if( $xml_current_tag_state == "IMAGETYPE" ) {
$person_data[$person_counter]["imagetype"] = $data;
}

if( $xml_current_tag_state == "HEADLINE" ) {
$person_data[$person_counter]["headline"] = $data;
}
if( $xml_current_tag_state == "FILENAME" ) {
$person_data[$person_counter]["filename"] = $data;
}
}
if( !($xml_parser = xml_parser_create()) )
die("Couldn't create XML parser!");

xml_set_element_handler($xml_parser, "startElementHandler", "endElementHandler");
xml_set_character_data_handler($xml_parser, "characterDataHandler");
while( $data = fread($fp, 4096) )
{
if( !xml_parse($xml_parser, $data, feof($fp)) )
{
break; // get out of while loop if we're done with the file
}
}
xml_parser_free($xml_parser);
?>

$person_data is my array.

laserlight

Could you give an overview of what you are trying to do, and what you are dealing with? The parser code helps me understand a little more, yes, but at this point you need to formulate how you intend to proceed. Going into detail when the detail has no problems just makes things difficult.

j0hn_

Please forgive me, i'm finding this a bit tough, you are very kind to put up with me. Here is a link to the page that I'm working on

http://student.dcu.ie/~nevillj2/new_site/image.php?article=boxbody1. Its a website I'm working on for my internship.

Simply put I wan't to navigate through the images categorized as say 'boxbody' for example in my xml file. I have a way of parsing the xml file into my array. The value of $article is = $displayPic.

Do I need a seperate page ? I'm sorry this is so confusing.

laserlight

I think the solution is to change your link. Instead of having:

http://student.dcu.ie/~nevillj2/new_site/image.php?article=boxbody1

Use:

http://student.dcu.ie/~nevillj2/new_site/image.php?article=boxbody&n=1

So, the image number is separated from the image category. When concatenated, they form the image name.

In this way, you can subtract from the current image number to get the previous, and add to get the next.

To determine the first and last images for the category, use the array generated from the XML file. Note that when adding and subtracting, you have to check that the number is not less than the first or more than the last.

j0hn_

Hello again laserlight,

Thank you very much for your help thus far. I thought about what you suggested in your last post and it was of great help to me because I have the first, next and previous navigation links now working.

I simply changed my line of code that looked like this...

$displayPic = "$article" . ".jpg";

to this

$displayPic = "$article" . "$x" . ".jpg";

and I just used a value of 1 to echo the first and after that it was just a case of adding or subtracting 1 to navigate forward and back.

<?php
echo "<td class=bgwhite align=center height=52>";
echo "<a href=";
echo "image.php?article=";
echo $article;
echo "&x=";
echo "1";
echo ">first</a></td>";

echo "<td class=bgwhite align=center height=52>";
echo "<a href=";
echo "image.php?article=";
echo $article;
echo "&x=";
echo $x + 1;
echo ">next --> </a></td>";

echo "<td class=bgwhite align=center height=52>";
echo "<a href=";
echo "image.php?article=";
echo $article;
echo "&x=";
echo $x - 1;
echo "><-- previous </a></td>";
?>

Okay so, I'm still unsure how I'm going to go about getting the 'last' image displayed. If I use a variable called $lenghtOfArray and give that a value of count($person_data) that will give me the length of everything in my Array.

If I could just do a count of the images by imagetype that would give me a value I could use to navigate to the last image of that type.

How do I go about this please ?

laserlight

Well, you could loop through the array and add to a counter everytime a given image with a given imagetype is encountered.

j0hn_

Okay I'm nearly getting this but all i'm getting is the $lengthOfArray value for 'boxbody'. So if I click into 'van fitting services' and it throws up 3 thumbnails and I and go click on the first; it goes and displays the first image. But the link to the 'last' item is still saying...

http://student.dcu.ie/~nevillj2/new_site/image.php?article=vanfit&x=7

and it should be

http://student.dcu.ie/~nevillj2/new_site/image.php?article=vanfit&x=3

I'm using this for loop =>

$lengthOfArray = count($person_data);

for( $i=0 ; $i < $lengthOfArray ; ++$i )
{
$thisName = $person_data[$i]["imagetype"];
if ($thisName == $article) {
}
}

Any idea ?

j0hn_

Hi I have already had some great help from Laserlight but I was wondering if someone else could please look at my issue posted above. I need to be able to navigate to the last element in an array and I'm not getting anywhere with it. I'm under a lot of pressure to get this finished asap. If you have time, thank you.

laserlight

You need to find the last item's number separately.

j0hn_

Sorry Laserlight,

what do you mean by 'separately' ? All I seem to be able to do is manipulate an array for the items in the boxbody category.

I understand that my parser runs and digs out all items by imagetype and then places those in my array. If I print_r ($person_data) there is nothing but boxbody images referenced in the array.

What the story with my loop ? When you say seperately do I need to use an include file or a seperate page of code or something ???

j0hn_

Hey Laserlight,

I have taken another look at my array and I discovered there was a problem with my xml file. It was missing entries for images of type "vanfit" so I manually entered them back in to the file and my array now has 10 elements.

There are 3 entries for "vanfit" and 7 for "boxbody". I want to filter out everything but the "vanfit" ones. Then I can do a count of the number of elements in my array and use that to navigate to the last item.

Please, Please, Please how do I delete all of the other elements other than "vanfit" rom my array ??????

laserlight

how do I delete all of the other elements other than "vanfit" rom my array

Loop through the array and [man]unset/man those elements that do not have this "vanfit" criteria.

j0hn_

laserlight wrote:
Loop through the array and [man]unset/man those elements that do not have this "vanfit" criteria.

Thank you Laserlight you have been of great help and guidance to me on this. It was the way you worded your last reply that really helped me finish this.

<?php
$lengthOfArray=count($person_data);
for( $i=0 ; $i < $lengthOfArray ; ++$i )
{
$thisName = $person_data[$i]["imagetype"];
if ($thisName != $article) {
unset($person_data[$i]);
}
}
$person_data = array_values($person_data);
print_r ($person_data);
$lengthOfArray=count($person_data);
?>

So now my loop looks through the array and removes any elements that are not equal to the "vanfit" criteria.

And my link to navigate to the last element of the array looks like this...

<?php
echo "<td class=bgwhite align=center height=52>";
echo "<a href=";
echo "image.php?article=";
echo $article;
echo "&x=";
echo $lengthOfArray;
echo ">last</a></td>";
?>