匹配mongodb php的元素

Question

my question is how I can translate into php the following js code from mongodb :

t.find( { group:3, 'x.a':2 }, { 'x.$':1 } ).toArray()[0].x.length, "single object match (array length match)" );

You can find the whole js code at :

https://github.com/mongodb/mongo/blob/83ec59844bdd629b2b32a9791a4e7a0e93516c02/jstests/elemMatchProjection.js

Basically what I care about is how can I translate into php toArray()[0].x.length ? I know php has count but I don't care about that. I have other advanced queries and all of them reduce to this question.

Answer 1

The literal translation of toArray()[0].x.length would be:

$cursor = $collection->find(['group' => 3, 'x.a' => 2], ['x.$' => 1]);
$documents = iterator_to_array($cursor, false);
count($documents[0]['x']);

Alternatively, it would be easier to use MongoCollection::findOne() in the above example, since we're only working with the first result and ignoring any others. Rewritten:

$document = $collection->findOne(['group' => 3, 'x.a' => 2], ['x.$' => 1]);
count($document['x']);

I didn't follow what you mean by "I know php has count but I don't care about that." Unless you were referring to MongoCollection::count() , the basic count() is necessary to calculate the length of the array in the returned document.