You can use 'ifelse': > x <- data.frame(id=sample(1:4,20,TRUE)) > # use ifelse to do the calculations > x$cal <- ifelse(x$id == 1, 21, + ifelse(x$id == 2, 221, + ifelse(x$id == 3, 2221, 22221))) > x id cal 1 4 22221 2 1 21 3 3 2221 4 1 21 5 2 221 6 2 221 7 1 21 8 2 221 9 4 22221 10 2 221 11 2 221 12 3 2221 13 2 221 14 1 21 15 4 22221 16 3 2221 17 4 22221 18 1 21 19 3 2221 20 2 221
On Mon, Feb 9, 2009 at 5:11 PM, Jesús Guillermo Andrade <jgandra...@mac.com> wrote: > Dear Sirs: I've been working with several variables in a dataframe > that serve as part of a calculation that I need to perform in a > different way depending on its value. Let me explain: > > The main dataframe is called llmcc > > llmcc : 'data.frame': 283 obs. of 11 variables: > $ Area : num 308.8 105.6 51.4 51.4 52.9 ... > $ mFondo : num 30.1 10 10.2 10.2 40.4 ... > $ mFachada : num 22.95 6.7 4.72 4.72 4.72 ... > $ Marca : Factor w/ 132 levels "AA_Movilnet",..: 11 32 82 82 32 > 32 32 32 32 32 ... > $ Clase : int 8 4 1 1 1 1 1 1 12 1 ... > $ Categoria: int 2 6 6 6 1 1 1 1 1 1 ... > $ Phi : num 0.128 0.147 0.217 0.217 0.887 ... > $ Rf : num 0.119 0.102 0.147 0.147 0.143 ... > $ OldA : num 0.737 0.258 0.375 0.375 0.385 ... > $ OldCondo : num 4436 1555 2260 2260 2318 ... > $ NewA_Jon : num 1.069 0.368 0.256 0.256 0.264 ... > > I perform an initial operation using the original variables plus one > numeric (Abase) that is external and has the same number of rows than > the dataframe: > > alitemp <- ((Abase/llmcc$Clase)*PClase)+(((1/llmcc > $Categoria)*Abase)*PCategoria)+((Abase*llmcc$Phi)*PPhi)+((Abase*llmcc > $Rf)*PRf) > > So, after I obtain the results of this calculation, I append the > series by creating an additional column within the original dataframe: > l > lmcc$Alitmp <- alitemp > > Problem is: I need to calculate a new column using a formula that has > different structure depending on the values of llmcc$Clase, thus: for > any given row of llmcc where llmcc$Clase is >= 10 i would have to > perform some operations with other values in the same row that are, by > definition, different than the ones I would need in case of lmcc$Clase > is < 10. > I've managed to break down the original dataframe by using subsets, > and then performing the calculations, but then it is complicated to > put the results in the same order of the original dataframe. > I understand the workings of the control structures available in R but > after reading the docs and help files, I can´t figure how to perform a > conditional calculation row by row that checks first the values of a > given column and then applies the corresponding operation to another > column, so it outputs a series in the same exact order as the dataframe. > > Any light that you might share with me over this will be highly > appreciated. > > Thanks in advance. > > > Guillermo. > > > > Nunca le preguntes a un peluquero si necesitas un corte de pelo. Ley > de Murray. > ------------------------------ > Jesús Guillermo Andrade (Abg.) > Gerente de Litigios y Corporativo. EDM. AC. API. > Andrade & Moreno S.C. (http://amlegal.wordpress.com/) > > > [[alternative HTML version deleted]] > > > ______________________________________________ > 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. > > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.
