Removing "NA" from matrix
On Jun 14, 2013, at 7:03 AM, Katherine Gobin wrote:
Dear R forum, I have a data frame dat = data.frame( ABC = c(25.28000732,48.33857234,19.8013245,10.68361461), DEF = c(14.02722251,10.57985168,11.81890316,21.40171514), GHI = c(1,1,1,1), JKL = c(45.96423231,44.52986236,16.56514176,32.14545122), MNO = c(45.38438063,15.54338206,18.78444777,24.29486984))
dat
ABC DEF GHI JKL MNO 1 25.28001 14.02722 1 45.96423 45.38438 2 48.33857 10.57985 1 44.52986 15.54338 3 19.80132 11.81890 1 16.56514 18.78445 4 10.68361 21.40172 1 32.14545 24.29487 When I try to find the correlation I get (which is obvious as my one column shows no variation)
Perhaps: dat_cor = cor(dat[ , sapply(dat, function(col) sd(col) != 0 ) ] )
Warning message: In cor(dat) : the standard deviation is zero
dat_cor
ABC DEF GHI JKL MNO ABC 1.0000000 -0.75600764 NA 0.55245223 -0.2735585 DEF -0.7560076 1.00000000 NA -0.06479082 0.2020781 GHI NA NA 1 NA NA JKL 0.5524522 -0.06479082 NA 1.00000000 0.4564568 MNO -0.2735585 0.20207810 NA 0.45645683 1.0000000 In reality I am dealing with about 300 variables and don't know which variables don't vary. My query is how do I remove the columns and rows with NA's. So for example, I need the correlation matrix for ABC, DEF, JKL and MNO only. Kindly guide. Thanking in advance. Regards Katherine [[alternative HTML version deleted]]
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