I have list of supermarket than contains list of ailes that contains list of specificAiles that contains list of products.
The idea is to get the product that have the nearest date of expiration.
I need to use java 8 streams to do so
Help please
You should be able to use flatMap to flatten the lists:
list.stream()
.flatMap(Collection::stream)
.flatMap(Collection::stream)
...
where ... is where you find the product in the flattened list with the "nearest expiration".
The javadoc for flatMap says:
Returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
Related
So I'm trying to get my head around the aggregate function in Parse Server with no luck so far!
Here's what I'm trying to establish:
Say I have a collection named Group, this class contains a list of groups created by users, each record in the group contains a field which is an array of Tag pointers (another collection).
The _User collection also contains an array of pointers named "tags".
What I'm trying to establish, is to get the list of all the groups along with the list of users matching at least one of the tags in the tags array of the Group collection.
I'm pretty sure that this can be done with the aggregate function but I've been trying for hours with no luck!
Any help would be greatly appreciated.
Thanks!
I've got a bunch of ES documents that I'd like to put into "collections". Each document has a unique integer as an ID. Each collection also needs to have a unique integer as an ID.
I need to be able to run queries to get a list of docs in a collection, and easily add an existing doc to a collection.
What would be the most efficient and logical way of approaching this:
An index of collections, which each has an array of document IDs, or
For each document have an array of integers (or a single integer) indicating to which collections it belongs?
Thank you.
I have a query that looks like:
r.table.orderBy(someIndex).group("someField")
Will the elements in each grouped stream be sorted by someIndex as well?
Yes, group should preserve the ordering of the stream it was called on.
What would be the best way to add objects into my LinkedList in alphabetical order of one of the objects parameters? I have a class that takes in last name, first name, and some other stuff. I've made an object of that class and the parameters are all user submitted, and I have to store every object that's made into a LinkedList. The objects must be added to the linked list in alphabetical order according to the last name. What would be the best way to do this?
Thanks!!
You could do a binary search through your list using the “compareTo” function to find the correct index in which to insert the new value.
The binary search consists in comparing the middle element key value with a given key, in this case, your new element. If the key match you are done, that is the correct index, if it does not but the value is greater than your key value you have to do the search again with the left half of the array, on the contrary, you do the search again with the right half
Is there a name for a list data structure where all of the elements have a pointer to the list or another common object? The list maintains this relationship by setting the pointer when items are added, and removing them when items are removed.
The purpose of the structure is to provide a way to find the common object from an element given that you don't want to pass the common object around everywhere.
A graph.