How to retrive a specific tag?

[littlebear0871]

HI there! I am trying to retrieve "doi" of each article, by using foreach() method. A error is reported:Warning: Illegal string offset 'doi'. following is the code:

foreach ($entries as $entrie) {
    foreach ($entrie as $bibitem) {
        echo $bibitem['doi'];
    }

Is any shortcut or method available to get certain tag?

Thakn you very much!

[renanbr]

The warning is about the missing tag in at least one of the entries.

To avoid this warning, you can either check if the tag is available before reading it ...

$doi = $bibteim['doi'] ?? null; // PHP 7+

... or add the FillMissingProcessor to the Listener in order to make sure this key is always available.

[renanbr]

reviewing the snippet you shared, I would say it should look like this:

foreach ($entries as $bibteim) {
    $doi = $bibteim['doi'] ?? null;
}

you're actually iterating over the tags in the inner foreach