Hi, I like the aggregate version. Here is an implementation with sapply and apply:
> data X2 gbm_tcga lusc_tcga ucec_tcga_pub 1 gbm_tcga 1.000000000 0.14053719 -0.102847164 2 gbm_tcga 1.000000000 0.04413434 0.013568055 3 gbm_tcga 1.000000000 -0.20003971 0.038971817 4 gbm_tcga 1.000000000 0.14569916 0.009947045 5 lusc_tcga 0.140537191 1.00000000 0.133080708 6 lusc_tcga 0.044134345 1.00000000 0.062024713 7 lusc_tcga -0.200039712 1.00000000 -0.130239551 8 lusc_tcga 0.145699156 1.00000000 0.041796670 9 ucec_tcga_pub -0.102847164 0.13308071 1.000000000 10 ucec_tcga_pub 0.013568055 0.06202471 1.000000000 11 ucec_tcga_pub 0.038971817 -0.13023955 1.000000000 12 ucec_tcga_pub 0.009947045 0.04179667 1.000000000 > sapply(levels(data[,1]),function(x) > apply(abs(data[as.character(data$X2)==as.character(x),-1])>0.2,2,sum)) gbm_tcga lusc_tcga ucec_tcga_pub gbm_tcga 4 1 0 lusc_tcga 1 4 0 ucec_tcga_pub 0 0 4 -- View this message in context: http://r.789695.n4.nabble.com/compute-values-by-condition-in-DF-by-rownames-tp4703351p4703387.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.