Thank you, David. This solves the problem.
Regards, Martin On Sun, Oct 25, 2015 at 12:53 PM, David L Carlson <dcarl...@tamu.edu> wrote: > It looks like the y2z() function strips NA's so that the vector lengths do > not match any longer. The simplest workaround is to remove the NA's. You > could do that by using data2 <- na.omit(data) to strip the observations > with NA if they will not be used in the rest of the analysis. > > If you want to preserve the NAs in the data frame, this seems to work: > > > nomiss <- complete.cases(data) > > data$zeta[nomiss] <- with(data[nomiss, ], y2z(weight, age/12, sex, > ref=who.wgt)) > > data > sex weight age zeta > 1 M 8.5 8 -0.124 > 2 M 8.2 9 -0.751 > 3 M 9.0 12 -0.635 > 4 F NA 9 NA > 5 M 5.8 1 2.002 > > > David L. Carlson > Department of Anthropology > Texas A&M University > > > > -----Original Message----- > From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Martin > Canon > Sent: Sunday, October 25, 2015 7:03 AM > To: R help <r-help@r-project.org> > Subject: [R] y2z question (AGD) > > Hi to all. > > I've been trying to calculate weight-for-age z-scores with the y2z > command (AGD package). > > However, I keep getting strange results. > > My hypothesis is that missings are the problem. > > My dataframe looks like this: > > data <- structure(list(sex = structure(c(3L, 3L, 3L, 2L, 3L), .Label = > c("", > "F", "M"), class = "factor"), weight = c(8.5, 8.2, 9, NA, 5.8), > age = c(8, 9, 12, 9, 1)), .Names = c("sex", "weight", "age" > ), class = "data.frame", row.names = c(NA, 5L)) > > Weight is in kg and age in months. > I will use WHO curves for children younger than 2 years of age. > > z-score calculation: > > library(AGD) > data$zeta <- y2z(y = data$weight, x = data$age/12, sex = data$sex, > ref = get("who.wgt")) > > I get: > > Warning message: > In `split<-.default`(`*tmp*`, f, drop = drop, value = value) : > number of items to replace is not a multiple of replacement length > > data$zeta > [1] NA NA NA -0.124 NA > > However a for loop seems to work. > > for (i in 1:5) { > > data$zeta[i] <- y2z(y = data$weight[i], > x = data$age[i]/12, > sex = data$sex[i], > ref = get("who.wgt")) > } > > data$zeta > [1] -0.124 -0.751 -0.635 NA 2.002 > > Is there a workaround so that I don't have to use a for loop? > na.action doesn't work either. > > Thanks. > > > Martin > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.
