Dear All,
I am new to R and slowly learning how to use the system.
The following code is an exercise I was trying.
The intent is to generate 10 random samples of size 5 from
a vector with integers 1:10 and 2 missing values. I then want
to generate a matrix, for each sample which shows the frequency
of missing values (NA) in each sample. My solution, using sapply
is at the end.
If anyone has the time and/or intrest to critique my method I'd
be very grateful. I'm especially interested in knowing if there is
a better way to accomplish this problem.
(x<-replicate(10,sample(c(1:10,rep(NA,2)),5)))
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 3 NA 3 4 2 10 NA 4 5 4
[2,] 5 7 7 3 9 2 8 NA 7 9
[3,] NA 8 1 5 NA 7 10 2 NA 6
[4,] 2 NA 6 10 8 4 4 7 4 7
[5,] 7 9 10 8 3 6 1 NA 9 NA
# Since table will return only a single item of vaule FALSE
# if there are no missing values (NA) in a sample, sapply
# will return a list and not a matrix.
# So to get a matrix, the factor function needs to be used
# to identify possible results (FALSE, TRUE) for the table
# function.
sapply(1:10,function(i) table(factor(is.na(x[,i]),c(FALSE,TRUE))))
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
FALSE 4 3 5 5 4 5 4 3 4 4
TRUE 1 2 0 0 1 0 1 2 1 1
Thanks for your thoughts.
Murray M Cooper, Ph.D.
Richland Statistics
9800 N 24th St
Richland, MI, USA 49083
Mail: richs...@earthlink.net
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
