PHP getting a specific key value at a specfic index in an array

Question

I've looked a bunch on here, and I've seem some similar type of questions, but none of them seemed to work in my situation (or at least I couldn't make them work), so hopefully this isn't an exact repeat.

I built an array that looks as follows:

Array
(
[0] => Array
    (
        [article_id] => 1
        [article_title] => Article 1
        [article_content] => This is some dummy text for the first article.
    )

[1] => Array
    (
        [article_id] => 2
        [article_title] => Article 2
        [article_content] => This is the content for article #2
    )
)

So the array has 3 keys (article_id, article_title, article_content), and what I'm trying to do is get a specific value at a specific index.

So, for example, if the page url is

/article.php?id=1

I first assign the id to a variable:

$linkID = $_GET['id'];

and now I want to search the array to find an article id match (to the $LinkID variable):

$foundAtPos = array_search($linkID, array_column($datas, 'article_id'));

this works fine, and gives me a matching "index" position, which is a great start, and now I want to assign the other two key values to variables (or echo them to the screen, something to show me that I've retrieved the correct id - article_title value).

This is the part where I get really stuck. I can easily display all values from the array, but I'm not looking to do that. I want to get ONLY the specific values that match the corresponding article_id.

Here's a few things I've tried (unsuccessfully):

    foreach ($datas as $keyName) {
        echo $keyName['article_title'];
    }

This gives me all the article titles, but that's not what I'm aiming for.

This bit I got from another stack overflow post, and it seemed like it was close, but I couldn't adapt it correctly.

 foreach($datas as $firstKey => $firstValue) {
  echo array_keys($firstValue, $firstValue['article_title'])[0].': '.$firstValue['article_title'].'</br>';
}

Same problem, gives me all the data, not just the row I'm trying to retrieve.

So I've gone in circles for hours, and it seems like this should be a common thing, but it's eluding me at the moment, so I'd appreciate any suggestions you fine folks might have.

Here's my entire function, for reference.

if (isset($_GET['id'])) {
    $linkID = $_GET['id'];

    foreach ($datas as $keyName) {
        //echo $keyName['article_title'];
    }

   //foreach($datas as $firstKey => $firstValue) {
  //echo array_keys($firstValue, $firstValue['article_title'])[0].': '.$firstValue['article_title'].'</br>';
//}

    //retrieve index of match in array
    $foundAtPos = array_search($linkID, array_column($datas, 'article_id'));

    print_r($datas[$foundAtPos]);


} else {
    header('Location: index.php');
    exit();
}

thanks!

try echo $datas[$foundAtPos]['article_title'];

musafar006
– musafar006

2018-12-27 02:18:43 +00:00
Commented Dec 27, 2018 at 2:18 — musafar006
– musafar006, Commented Dec 27, 2018 at 2:18

Will B. · Accepted Answer · 2018-12-27 02:56:03Z

1

You can simplify this a lot by just using array_column with null as the $column_key argument.

This will re-index the entire array with the article_id.

Array
(
[1] => Array
    (
        [article_id] => 1
        [article_title] => Article 1
        [article_content] => This is some dummy text for the first article.
    )

[2] => Array
    (
        [article_id] => 2
        [article_title] => Article 2
        [article_content] => This is the content for article #2
    )
)

Then you can use isset on the $linkID of the resulting array.

Example: https://3v4l.org/Fmj9K

if (isset($_GET['id'])) {
    $linkID = $_GET['id'];

    $articles = array_column($datas, null, 'article_id');
    if (isset($articles[$linkID])) {
        $article = $articles[$linkID];
        //optionally convert from an array values to variable values.
        $article_title = $article['article_title'];
        $article_content = $article['article_content'];
    }
}

Or in PHP 7.1+ you can use list with the key names

Example: https://3v4l.org/C2c4K

if (isset($_GET['id'])) {
    $linkID = $_GET['id'];

    $articles = array_column($datas, null, 'article_id');
    if (isset($articles[$linkID])) {
        list('article_title' => $title, 'article_content' => $content) = $articles[$linkID];
    }
}

answered Dec 27, 2018 at 2:56

Will B.

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2 Comments

miken32 Over a year ago

Nice one, I always forget about the third argument to array_column()

Nick Over a year ago

Wow, how awesome. While I don't fully understand it yet, your answer will definitely aid in my php learning. Thanks so much for this! :)

Dharman · Accepted Answer · 2018-12-27 13:53:32Z

0

If you already know the ID then just loop on that sub-array:

$foundAtPos = array_search($linkID, array_column($datas, 'article_id'));
foreach ($datas[$foundAtPos] as $key => $value) {
    echo $key . ': '. $value;
}

or if you want to get a specific key/value pair at some index then you can use the bracket operator:

$foundAtPos = array_search($linkID, array_column($datas, 'article_id'));
echo $datas[$foundAtPos]['article_title'];

edited Dec 27, 2018 at 13:53

answered Dec 27, 2018 at 1:56

Dharman♦

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2 Comments

Nick Over a year ago

Well, I'm not even sure a loop is entirely necessary, it's just I haven't figured out how to get at a specific key/value at a specific index in the array.

Nick Over a year ago

so your suggestion gets me the correct row, and produes the following output..article_id: 2article_title: Article 2article_content: This is the content for article #2 (this is what I expect to get), however what I need to do is break this up and get only the article_title or article_content for this row, and I'm stumped as how to do that

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