[RESOLVED] list instead of associative array

jrough

I am getting this result which is not what I want.
634332024array(1) { [0]=> int(1634332024) }

I want an associative array of ids like
ids[0] = xxxx,
ids[1] =xxxxx,
ids[2]=xxxx

I know you don't need the index but how else do you keep track of the ones you have used?
SHould this be a list data structure or is something wrong with the function?

function foo($j) {

   $ids= array();
   $i=0;
    while (count($ids) < $j) {

$id = gen_id();  // assume this function will return you an integer
    if (!in_array($id, $ids[$i]))  {
        $ids[$i]= $id;
         $i++;}   
  }
return $ids;
    }


function gen_id(){
  $c=rand (0, getrandmax());
	 echo $c;
	return $c;

}


$ids = foo(10);
var_dump($ids);

thanks,

dagon

jrough;11003357 wrote:
I know you don't need the index but how else do you keep track of the ones you have used?

you don't php is cleaver

$foo[]='a';
$foo[]='b';
$foo[]='c';

print_r($foo)

dalecosp

dagon;11003362 wrote:
you don't php is clever
$foo[]='a';
$foo[]='b';
$foo[]='c';

print_r($foo)

Not only that, but this isn't an "associative" array. It's a indexed/numbered array.

//THIS is an associative array.
<?php

$girls=array();
$girls['sis']="ok";
$girls['mom']="ok";
$girls['megan_fox']="wowsa!";

jrough

this isn't the right answer, it needs to be a linked list so you given out the first id, and then next one and keep track of what numbers you have given out by using the index. You can keep adding to the end. In an array you cannot keep adding indefinitely.

NogDog

Perhaps I'm misunderstanding you, but the point is that in an enumerated array, you do not need to keep track of the array indexes since PHP will do it automatically for you, e.g.:

function foo($j) {

  $ids= array();
  while (count($ids) < $j) {

  $id = gen_id();  // assume this function will return you an integer
    if (!in_array($id, $ids))  {
      $ids[]= $id;
    }
  }
  return $ids;
}

(untested)

Bonesnap

jrough;11003366 wrote:
this isn't the right answer, it needs to be a linked list so you given out the first id, and then next one and keep track of what numbers you have given out by using the index.

There is no "linked list" in PHP, but in any case I don't see why you can't keep track of the indexes with the solution provided.

jrough;11003366 wrote:
You can keep adding to the end. In an array you cannot keep adding indefinitely.

Yes you can. You're limited more by the script's execution time and allowed memory than the number of elements in an array.

jrough

that helped with one problem, I didn't need the i++ counter so that is why that function doesn't work. The other problem is I am trying to implement a different data structure, a list and I don't know how but I'll try to find it on the internet. Thanks,

Derokorian

Actually this line was the problem:

        if (!in_array($id, $ids[$i]))  {

If display_errors were turned on, and error_reporting were set to E_ALL (or better) you would get an undefined index error on this line and/or invalid parameter. Since any offset in the $ids array will not itself be an array.

Bonesnap

jrough;11003370 wrote:
that helped with one problem, I didn't need the i++ counter so that is why that function doesn't work. The other problem is I am trying to implement a different data structure, a list and I don't know how but I'll try to find it on the internet. Thanks,

I think you might be misunderstanding arrays.

Let's say you have the following code:

$my_array = array();

$my_array[] = 'John';
$my_array[] = 'Debra';
$my_array[] = 'Lisa';
$my_array[] = 'David';

You now have an array with four elements. You don't need to keep track of the indexes because PHP does that for you. What you have is what's typically referred to as a numerically indexed array, or simply a numeric array. Meaning each element can be referenced by a numeric index. For example, let's say you wanted to print out "Lisa". You would only need to write:

echo $my_array[2]; //Remember, arrays are 0-based so the first element is always 0.

And that's it. No worrying about what indexes you've used or "how many are left". You can add and remove from the array without worry, and there's no need to go hunting for any kind of special data structure.

jrough

thanks for the clarification!😃