jblood94 questions

jblood94 answers

• Vectorize an sapply function
• Find every combination meeting constraints
• Filtering the Results of Expand.Grid
• Compute N random permutations of a vector of 36 elements
• How can this R data.table join+group+summarise, operation be made a lot faster?
• Export different subsets of data.tables to each node in a cluster
• How to efficiently divide pairs into clusters such that each cluster contains all entries of a given set
• Select one of many-to-many matches between data.table dt1$id and dt2$id such that dt1$id and dt2$id are unique in the result set
• Vectorizing loops in R
• Why does R allow new column creation via tail-slicing?