greater than symbol for find() method in php7 mongodb - mongodb

Question

I am developing a php-mongodb project. I have installed the php-mongodb driver using composer. connectivity is working fine.
used reference link for any guidance :
http://mongodb.github.io/mongo-php-library/tutorial/crud/#crud-operations
and http://php.net/manual/en/mongocollection.find.php
I could not find much reliable theory for php-7 except those.
How to fire a query with php-7 to get a result from database greater than specified number?
The code I tried is :
$rs=$collection->find(['$gte'=>['avg'=>50]]);
this is not working. The error it produced was:
Fatal error: Uncaught MongoDB\Driver\Exception\ConnectionException: unknown top level operator: $gte in /var/www/example.com/public_html/vendor/mongodb/mongodb/src/Operation/Find.php:180 Stack trace: #0 /var/www/example.com/public_html/vendor/mongodb/mongodb/src/Operation/Find.php(180): MongoDB\Driver\Server->executeQuery('training.tbl', Object(MongoDB\Driver\Query), Object(MongoDB\Driver\ReadPreference))#1 /var/www/example.com/public_html/vendor/mongodb/mongodb/src/Collection.php(437): MongoDB\Operation\Find->execute(Object(MongoDB\Driver\Server)) #2 /var/www/example.com/public_html/list.php(5): MongoDB\Collection->find(Array) #3 {main} thrown in /var/www/example.com/public_html/vendor/mongodb/mongodb/src/Operation/Find.php on line 180

Answer 1

found this answer from following here
// search for documents where 5 < x < 20
$rangeQuery = array('x' => array( '$gt' => 5, '$lt' => 20 ));
for above example the answer comes to be:
$rangeQuery = ['avg' => ['$gt' => '50' ]];
$rs=$collection->find($rangeQuery);