[R] SApply versus for loop for list of data.frames

[David Winsemius]

On Oct 12, 2010, at 12:16 AM, rivercode wrote:

>
> Hi,
>
> I am trying to find the total number of rows for a list of  
> data.frames and
> want to know if there is a better way than using a loop like:
>
>> df = { list of data.frame with varying number of rows...each one  
>> has a
> column called "COL" }
>> r = 0
>> for (i in 1:length(df)) {
> + r = r + length(n[[i]]$CON)
> + }
>> r
> 6000123   <----  number of rows.


r <- lapply(df, NROW)
r

-- 
David.