Note that in Variable <- 0 + (item1 == 1) + (item2 == 1) + (item3 == 1) + (item4 == 1) the '0 +' is not needed, since adding logicals produces integers.
Your second solution Variable <- sum((item1 == 1), (item2 == 1) , (item3 == 1) , (item4 == 1), na.rm=TRUE) gives the wrong answer, since sum() always returns a scalar. You could treat logical NA's as FALSE's by defining is.true <- function(x) !is.na(x) & x and using it as Variable <- is.true(item1==1) + is.true(item2==1) + is.true(item3==1) + is.true(item4==1) Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of Jeremy Miles > Sent: Monday, February 25, 2013 5:41 PM > To: Craig J > Cc: r-help > Subject: Re: [R] Converting code to R Question > > Here's a direct translation: > Variable <- 0 > Variable <- ifelse(item1 == 1, Variable +1, Variable) > Variable <- ifelse(item2 == 1, Variable +1, Variable) > Variable <- ifelse(item3 == 1, Variable +1, Variable) > Variable <- ifelse(item4 == 1, Variable +1, Variable) > > Here's another way to do it: > > Variable <- 0 + (item1 == 1) + (item2 == 1) + (item3 == 1) + (item4 == 1) > > Note that I haven't worried about missing data - do you have NAs in > your items? If you do, and you want NA to be not equal to 1 (rather > than equal to NA): > > Variable <- sum((item1 == 1), (item2 == 1) , (item3 == 1) , (item4 == > 1), na.rm=TRUE) > > > Jeremy > > > On 25 February 2013 17:02, Craig J <cjohn...@gmail.com> wrote: > > I'm learning R and am converting some code from SPSS into R. My background > > is in SAS/SPSS so the vectorization is new to me and I'm trying to learn > > how to NOT use loops...or use them sparingly. I'm wondering what the > > most efficient to tackle a problem I'm working on is. Below is an example > > piece of code. Essentially what it does is set a variable to zero, loop > > through item responses, and add one if a condition is met. For example, if > > item one was responded as a 1 then add one to the final variable. If item > > two was responded as a 2 then add one to the final variable. I have to do > > this for five scales with each scale having 6 items half of which may have > > the 1 response pattern and half the 2 pattern. > > > > Any suggestions on how best to tackle this in R would be helpful. > > > > Craig > > > > ********** > > Old SPSS code sample > > ********** > > > > Compute Variable = 0. > > > > IF (item1 = 1) Variable = Variable +1 . > > > > IF (item2= 2) Variable = Variable +1 . > > > > IF (item3 = 1) Variable = Variable +1. > > > > IF (item4 = 2) Variable = Variable +1. > > > > EXECUTE . > > > > [[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. > > ______________________________________________ > 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.
