Category "aggregate"

Can list comprehensions make groups?

I have a list that looks like [(1,2,5),(2,10,13),(5,24,56),(1,8,10),(2,3,11)] How can I produce a dictionary by grouping by first element of tuples and find

Earliest Date for each id in R

I have a dataset where each individual (id) has an e_date, and since each individual could have more than one e_date, I'm trying to get the earliest date for ea

Simple aggregation by id variables in R

I'm having a problem with the aggregate function. My data.frame looks like this: **Region Sex SNI value** orebro Man 0 497 orebro

Getting error while running the aggregate method of MognoDB

I am getting the following error while joining two collection and project the fields using MognoDB. Error:: Error: command failed: { "ok" : 0, "er

MongoDB Merge Equivalent Collections

I have two collections with same structure and want to merge them in aggregation result and query & sort over them after merging. E.g.; First collection: