Given two data frames: df1 = data.frame(CustomerId = c(1:6), Product = c(rep("Toaster", 3), rep("Radio", 3))) df2 = data.frame(CustomerId = c(2, 4, 6), State = c(rep("Alabama", 2), rep("Ohio", 1))) ...
I have a list of many data.frames that I want to merge. The issue here is that each data.frame differs in terms of the number of rows and columns, but they all share the key variables (which I've call...
Consider the following scenario: I have developed a small experimental project A in its own Git repo. It has now matured, and I'd like A to be part of larger project B, which has its own big reposito...
You know, I haven't seen a good answer for this anywhere. Is it possible to embed a pre-existing DLL into a compiled C# executable (so that you only have one file to distribute)? If it is possible, ho...
Very simplified, I have two tables Source and Target. declare @Source table (SourceID int identity(1,2), SourceName varchar(50)) declare @Target table (TargetID int identity(2,2), TargetName varchar(...
Consider the following data.tables. The first defines a set of regions with start and end positions for each group library(data.table) d1 <- data.table(x=letters[1:5], start=c(1,5,19,30, 7), end=...
I have forked a branch from a repository in GitHub and committed something specific to me. Now I found the original repository had a good feature which was at HEAD. I want to merge it only without pr...
EntityManager.merge() can insert new objects and update existing ones. Why would one want to use persist() (which can only create new objects)?
The UPSERT operation either updates or inserts a row in a table, depending if the table already has a row that matches the data: if table t has a row exists that has key X: update t set mystuff.....