Performing regex queries with PyMongo
To avoid the double compilation you can use the bson regex wrapper that comes with PyMongo:
>>> regx = bson.regex.Regex('^foo')>>> db.users.find_one({"files": regx})Regex just stores the string without trying to compile it, so find_one can then detect the argument as a 'Regex' type and form the appropriate Mongo query.
I feel this way is slightly more Pythonic than the other top answer, e.g.:
>>> db.collectionname.find({'files':{'$regex':'^File'}})It's worth reading up on the bson Regex documentation if you plan to use regex queries because there are some caveats.