This behavior isn’t related to $lookup, it’s because the default behavior for $unwind is to omit documents where the referenced field is missing or an empty array. To preserve the unwound documents even when profile.universities is an empty array, you can set its preserveNullAndEmptyArrays option to true: db.users.aggregate([ { $unwind: “$profile”, $unwind: { path: “$profile.universities”, … Read more
A dictionary is not the appropriate data structure for the operations you are describing. If the intervals are required to never overlap then you can just build a sorted list of intervals and binary search it. If the intervals can overlap then you have a more difficult problem to solve. To solve that problem efficiently … Read more
You can use $lookup 3.6 syntax to $project the fields inside the $lookup pipeline User.aggregate([ { “$lookup”: { “from”: “schedules”, “let”: { “id”: “$_id.phone” }, “pipeline”: [ { “$match”: { “$expr”: { “$eq”: [“$customer.phone”, “$$id”] }}}, { “$project”: { “scheduleStart”: 1, “scheduleEnd”: 1 }} ], “as”: “user_detail” }} ])
I don’t think the array that has 5 elements is good case to check time complexity. So based on @Shidersz’s snippet, I made a new one that has many elements and invoked once. Is Set.has() really O(1) ? Yes. Time complexity of Set.has() is O(1) according to result of the test below. const MAX = … Read more
Use HashSet instead. It’s a hash implementation of Set, which is used primarily for exactly what you describe (an unordered set of items).
If you want to run this with new TF 2.x code with eager execution enabled by default. Below is the quick code snippet. import tensorflow as tf # build a lookup table table = tf.lookup.StaticHashTable( initializer=tf.lookup.KeyValueTensorInitializer( keys=tf.constant([0, 1, 2, 3]), values=tf.constant([10, 11, 12, 13]), ), default_value=tf.constant(-1), name=”class_weight” ) # now let us do a lookup … Read more
It looks like what you’re doing here is effectively a “gather”. Modern CPUs have dedicated instructions for this, in particular VPGATHER** . This is exposed in .NET Core 3, and should work something like below, which is the single loop scenario (you can probably work from here to get the double-loop version); results first: AVX … Read more
You can use HashSet<T>. The HashSet<T> class provides high-performance set operations. A set is a collection that contains no duplicate elements, and whose elements are in no particular order.
It is because name lookup stops if it finds a name in one of your bases. It won’t look beyond in other bases. The function in B shadows the function in A. You have to re-declare the function of A in the scope of B, so that both functions are visible from within B and … Read more