php multidimensional array iteration issue

Question

Consider having 4 different RSS news feeds URL's

$urls[0]['news'] = "url1";
$urls[1]['news'] = "url2";
$urls[2]['news'] = "url3";
$urls[3]['news'] = "url4";

The following function should get 4 news titles from each of the url's

function getRssFeeds($urls,$type){
        //Prepare XML objects
        $xmls[$type] = array();
        //Prepare item objects
        $items[$type] = array();
        //Prepare news titles/links arrays
        $article_titles[$type] = array();
        $encoded_titles[$type] = array();
        $article_links[$type] = array();
            //Fill XML objects
        for($i=0; $i<4; $i++){
            $xmls[$i][$type] = simplexml_load_file($urls[$i][$type]);
            //Prepare news items
            $items[$i][$type] = $xmls[$i][$type]->channel->item;
            for($i=0; $i<4; $i++){
                $article_titles[$i][$type] = $items[$i][$type]->title;
                $encoded_titles[$i][$type] = iconv("UTF-8","windows-1251",$article_titles[$i][$type]);
            }
            //$article_links[$type][$i] = $items[$type][$i]->link;
        }
        return $encoded_titles;
    }

After using the following to get the values:

 type='';
    function printRssFeed($urls,$type){
            $titles = getRssFeeds($urls,$type);
            foreach($titles as $title)
            {
                echo $title[$type]."<hr/>";
            }
        }

I get undefined offset error. If I remove the inner for loop of the getRssFeeds() function I get only 1 new title from each URL.

Why don't your write one function that works per feed and then just iterate over you data? That's what iterations are for: Do the same as for one but for multiple. — hakre
– hakre, Commented Oct 11, 2011 at 14:32
either just combine the data later on, or just iterate over your data again and display it. It's combined in the display then. Right now you're introducing too much logic into your function and that leads to errors because everything looks too complicated for you. Keep things simple, divide the tasks, that reduces possibilities of errors and will get you better code. — hakre
– hakre, Commented Oct 11, 2011 at 14:37

Laurence Burke · Accepted Answer · 2011-10-11 14:59:07Z

2

in this code you are resetting $i to 0 in your inner for loop.

 for($i=0; $i<4; $i++){
        $xmls[$i][$type] = simplexml_load_file($urls[$i][$type]);
        //Prepare news items
        $items[$i][$type] = $xmls[$i][$type]->channel->item;
        for($i=0; $i<4; $i++){
            $article_titles[$i][$type] = $items[$i][$type]->title;
            $encoded_titles[$i][$type] = iconv("UTF-8","windows-1251",$article_titles[$i][$type]);
        }
        //$article_links[$type][$i] = $items[$type][$i]->link;
    }

try changing your inner for loop variable to a different one. Also when you define your arrays it seems that you are not following the same structure.

$xmls[$i][$type] does not = your original instantiation of $xmls[$type] = array(); this is true for all your other arrays.

so I think your array structure is off because you add a top level of $type and then when you iterate you use a $i as you top level key.

try to remove the instantiations of the arrays in the beginning

function getRssFeeds($urls,$type){
    //Fill XML objects
    for($i=0; $i<4; $i++){
        $xmls[$i][$type] = simplexml_load_file($urls[$i][$type]);
        //Prepare news items
        $items[$i][$type] = $xmls[$i][$type]->channel->item;
        for($i=0; $i<4; $i++){
            $article_titles[$i][$type] = $items[$i][$type]->title;
            $encoded_titles[$i][$type] = iconv("UTF-8","windows-1251",$article_titles[$i][$type]);
        }
        //$article_links[$type][$i] = $items[$type][$i]->link;
    }
    return $encoded_titles;
}

edited Oct 11, 2011 at 14:59

answered Oct 11, 2011 at 14:36

Laurence Burke

2,35814 silver badges26 bronze badges

And how should I repair it. If I knew I wouldn't ask

George
– George

10/11/2011 14:55:31
Commented Oct 11, 2011 at 14:55
1

@george im thinking sorry for the wait

Laurence Burke
– Laurence Burke

10/11/2011 14:56:21
Commented Oct 11, 2011 at 14:56
@george try and get rid of all the initial instantiations. And if that doesnt fix it it may then be a structural iteration problem with your for looping

Laurence Burke
– Laurence Burke

10/11/2011 14:57:41
Commented Oct 11, 2011 at 14:57
could it be that you are not setting your $type = 'news'; before you printRSSFeeds???

Laurence Burke
– Laurence Burke

10/11/2011 15:02:03
Commented Oct 11, 2011 at 15:02
Maybe. Later I call the function with $type = 'sport' and $type = 'gossip'

George
– George

10/11/2011 15:04:34
Commented Oct 11, 2011 at 15:04

| Show 1 more comment

Punit · Accepted Answer · 2011-10-12 11:28:26Z

0

try this in your inner for loop

$j = 0;  
  for($j=0; $j<4; $j++){  
                $article_titles[$j][$type] = $items[$i][$type]->title;  
                $encoded_titles[$j][$type] = iconv("UTF-8","windows-1251",$article_titles[$j][$type]);  
            }

answered Oct 12, 2011 at 11:28

Punit

1,1201 gold badge8 silver badges15 bronze badges

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