On Thursday 30 May 2013 02:57:04 Camilo Mora wrote: > do you know why is this? or is there another way to sum by row in a > given number of columns? Without data.table:
x <- structure(list(col1 = c(NA, 0, -0.015038, 0.003817, -0.011407 ), col2 = c(0.003745, 0.007463, -0.007407, -0.003731, -0.007491 )), .Names = c("col1", "col2"), class = "data.frame", row.names = c(NA, -5L)) x[ is.na( x ) ] <- 0 x$col3 <- x$col1 + x$col2 > x col1 col2 col3 1 0.000000 0.003745 0.003745 2 0.000000 0.007463 0.007463 3 -0.015038 -0.007407 -0.022445 4 0.003817 -0.003731 0.000086 5 -0.011407 -0.007491 -0.018898 > > > > > # col1 col2 col3 > #1: NA 0.003745 0.003745 > #2: 0.000000 0.007463 0.007463 > #3: -0.015038 -0.007407 -0.022445 > #4: 0.003817 -0.003731 0.000086 > #5: -0.011407 -0.007491 -0.018898 > > ______________________________________________ > 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. ______________________________________________ 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.