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Aug 28th, 2010

Retrieving multidimensional array

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Hello,
In OOP PHP, i got 2 classes: Database and News. In News class i call DB function and get result (multidimensional 2D array). Now i have to display that array in index.php. I call News class (lets say get_news() function) from index.php but cant retrieve data and always get message: "Cannot use object of type News as array in ..."

Here is some of my code:
database.php

PHP Syntax (Toggle Plain Text)
class DB{
function news($user_id){
$q="select all from news where author id='$id'";
$result=$db->query($q);
for($i=0; $i<$r->num_rows; $i++){
  $arr[]=$result->fetch_array;
}
return $arr; //works fine!
}}
class DB{
function news($user_id){
$q="select all from news where author id='$id'";
$result=$db->query($q);
for($i=0; $i<$r->num_rows; $i++){
  $arr[]=$result->fetch_array;
}
return $arr; //works fine!
}}

news.php

PHP Syntax (Toggle Plain Text)
class News{
function get_news($user_id){
global $db;
$news=$db->news($user_id);
print_r($news);        // works fine!
return $news;
}}
class News{
function get_news($user_id){
global $db;
$news=$db->news($user_id);
print_r($news);        // works fine!
return $news;
}}

index.php // how to display data from News class (news.php)

PHP Syntax (Toggle Plain Text)
$post=new News;
$post->get_news($user_id);
.. i tried
for($i=0; $i<5; $i++){
  foreach($post[$i] as $k=>$v){
      echo $v;         //get error: "Cannot use object of type News as array in ..."
   }
}
$post=new News;
$post->get_news($user_id);
.. i tried
for($i=0; $i<5; $i++){
  foreach($post[$i] as $k=>$v){
      echo $v;         //get error: "Cannot use object of type News as array in ..."
   }
}

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newprimitive

Reputation Points: 10

Solved Threads: 2

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20 posts
since Aug 2010

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Aug 28th, 2010

Re: Retrieving multidimensional array

Generally, when a function/method call returns something, and you need that something later on, you need to "receive/assign" it to something else. Your $post->get_news($user_id); returns an array, but there is NOTHING "receiving" that array. Also, just because your method get_news() returns an array, it does NOT "overwrite" the $post variable. Thus, after the method call, the $post variable is still a 'News' object. So $post[$i] is not valid - again, because $post is NOT an array - it is still a News object. So try:

PHP Syntax (Toggle Plain Text)
$post=new News;
$data = $post->get_news($user_id);
 
//to verify that you got the array you were expecting
print_r($data);
 
for($i=0; $i<5; $i++){
  foreach($data[$i] as $k=>$v){
      echo $v; //get error: "Cannot use object of type News as array in ..."
   }
}
$post=new News;
$data = $post->get_news($user_id);

//to verify that you got the array you were expecting
print_r($data);

for($i=0; $i<5; $i++){
  foreach($data[$i] as $k=>$v){
      echo $v; //get error: "Cannot use object of type News as array in ..."
   }
}

On another note, the only similarity between your thread and the other was that both of you have the need to retrieve data from the db. You are way ahead of the game since you already have some php code in place that needs minor fixing. The other poster didn't seem to have anything in place yet.

Regards,
Hielo

hielo

Reputation Points: 116

Solved Threads: 243

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1,123 posts
since Dec 2007

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Aug 28th, 2010

Re: Retrieving multidimensional array

PHP Syntax (Toggle Plain Text)

$q="select all from news where author id='$id'";

Whuch Kind of database is his?
AFAIK, it should go like this:

PHP Syntax (Toggle Plain Text)

$q="SELECT * FROM news WHERE author id='$id'"

evstevemd

Reputation Points: 462

Solved Threads: 392

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3,681 posts
since Jun 2007

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Aug 29th, 2010

Re: Retrieving multidimensional array

Thanks Hielo, i totally forgot to put some variable that would receive returned value. To display retrieved data, one simple for loop worked just fine:

PHP Syntax (Toggle Plain Text)
for($i=0; $i<5; $i++){
    echo $data[$i]['title'].'<br />'.$data[$i]['body'].'<br />'..etc.;
}
for($i=0; $i<5; $i++){
    echo $data[$i]['title'].'<br />'.$data[$i]['body'].'<br />'..etc.;
}

newprimitive

Reputation Points: 10

Solved Threads: 2

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20 posts
since Aug 2010

Permalink

Aug 29th, 2010

Re: Retrieving multidimensional array

Click to Expand / Collapse Quote originally posted by newprimitive ...

Thanks Hielo, i totally forgot to put some variable that would receive returned value. To display retrieved data, one simple for loop worked just fine:
PHP Syntax (Toggle Plain Text)
for($i=0; $i<5; $i++){
    echo $data[$i]['title'].'<br />'.$data[$i]['body'].'<br />'..etc.;
}
for($i=0; $i<5; $i++){ echo $data[$i]['title'].'<br />'.$data[$i]['body'].'<br />'..etc.; }

Worked with that Query?

I'm curious what kind of DB you are using!

evstevemd

Reputation Points: 462

Solved Threads: 392

Senior Poster

Offline

3,681 posts
since Jun 2007

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