C# Driver, using linq's In operater ($in) for regex

[Sam Martin]

Hi all,

think this should be a simple one, but cant suss the syntax.

In mongo i can say

db.coll.find({ "myatt": { $in : [/^x/,/^y/]} });

Is this possible using the "In" linq to mongo extension method?

I've tried passing the string[] as regex string but no surprise didn't work, do I have to use Inject()?

TIA

Sam

[Robert Stam]

This can't really be expressed in standard LINQ because the types involved (string and BsonRegularExpression) are different. The standard LINQ Contains extension method (and the analogous LINQ to MongoDB In extension method) assumes that the value being tested and the source of values to test against are of the same type.

Inject seems like a good workaround.

Do you feel there should be a way to express this type-mismatched query directly in LINQ to MongoDB? If so, you could create a new JIRA issue requesting the feature.

Sam

--
You received this message because you are subscribed to the Google
Groups "mongodb-user" group.
To post to this group, send email to mongod...@googlegroups.com
To unsubscribe from this group, send email to
mongodb-user...@googlegroups.com
See also the IRC channel -- freenode.net#mongodb

[craiggwilson]

JIRA already exists: https://jira.mongodb.org/browse/CSHARP-495 and a related issue https://jira.mongodb.org/browse/CSHARP-493.  I have the code done for the fix, but we weren't (and still aren't) sure if this is supposed to work or if it just happens to work (and might go away later).

https://github.com/craiggwilson/mongo-csharp-driver/tree/csharp493_495

[AG]

Is there a way to express the $in query using regular expressions in the c# driver?

Something like this, but checking the regex against any member in the array?

Query.Matches("Series", BsonRegularExpression.Create(new Regex(searchPattern, RegexOptions.IgnoreCase)))

Thanks.

[Sam Martin]

here's one i've used a bit.

It returns documents where one of the elements in the series array exists in an collection of regular expressions created from a string array.

i.e. all docs where at least one of the Series elements starts with one of the items in my string array. /^xxxx/, /^yyyy/

_db.GetCollection("mycollection").Find(Query.In("Series", mystringrray.Select(p => BsonRegularExpression.Create("/^" + p + "/")));

does that help?

--