R help - Jan 2012 - Merging data XXXX

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

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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

On Jan 13, 2012, at 1:42 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
?rep
?data.frame

I would not think 'merge' is needed ... you just want to make the  
right number of copies and you should be paying attention to the  
'each' and 'times' parameters.
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