[R] Merging data XXXX

[Marc Schwartz]

On Jan 13, 2012, at 12:42 PM, Dan Abner wrote:

> Hello everyone,
> 
> I have 1 data frame (just a vector in the example below) with 12
> individuals listed and a separate vector of 36 days (in week intervals).
> What is the best way to merge these together so that each individual
> ("specialist" here) has all 36 days matched with their specialist number (a
> one to many merge in SAS; essentially resulting in long format data).
> 
> implement<-as.Date("2012-4-30")
> start<-implement-91
> weeks<-seq(start,by="weeks",length=36)
> weeks
> specialist<-1:12
> 
> 
> Thanks!
> 
> Dan


Two ways:

  merge(specialist, weeks)

  expand.grid(specialist, weeks)

See ?merge which performs a SQL-like join operation and ?expand.grid which provides for all possible combinations of two or more vectors

HTH,

Marc Schwartz