I have a collection with several fields, and I'd like to get the minimum value from one. I know a command for getting the max value:
collection.find_one(sort=[("myfield", -1)])["myfield"]
but not one for getting the min. Is there a way to do this?
You can reverse the sort direction to get the minimum instead of the maximum value:
# Sort by myfield (ascending value) and return first document
collection.find_one(sort=[("myfield", 1)])["myfield"]
This example assumes that:
myfield is a numeric value (so the sort order makes sense to determine a minimum or maximum)myfield exists in the matching document returned (otherwise Python will report a KeyError when trying to reference a non-existent field).myfield value (documents that have do not have a myfield value will sorted before the minimum numeric values)To ensure your sort is based on documents that actually have a myfield value you can add $exists to the query criteria:
collection.find_one({"myfield": {"$exists": True}}, sort=[("myfield", 1)])["myfield"]
For more information on sorting see:
