Test empty string in mongodb and pymongo

Question

Here is my data structure.

[{
\"name\": \"David\",
\"lastname\": \"\",
},
{
\"name\": \"Angela\"
}]

\"lastname\" is sometimes present and

Answer 1

Facing this problem I thought in another solution:

db.collection.find({"lastname": {"$gte": " "}})

With this I could get only the not empty strings, also ignoring null and not existent field, because any printable value (ASCII) has a greater value than space (32).

https://en.wikipedia.org/wiki/ASCII