[R] assigning letter to a column

[Monaly Mistry]

Thank you for your help David, will make sure to check the documentation.

Best,

Monaly

On Fri, Oct 17, 2014 at 3:27 PM, David L Carlson <dcarlson at tamu.edu> wrote:

> Minor correction, given your code, values less than 3 will be coded as "S"
> since they are less than 15.23. In the code I suggested, values less than 3
> will be coded as missing (NA).
>
> David C
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of David L Carlson
> Sent: Friday, October 17, 2014 9:15 AM
> To: Monaly Mistry; r-help at r-project.org
> Subject: Re: [R] assigning letter to a column
>
> I think it is doing exactly what you have told it to do, but that is
> probably not what you want it to do.
>
> First, you do not need a loop since the ifelse() function is vectorized.
> Read the manual page and the examples carefully. Also you are coding
> ifelse() as if it were the same as if() {} else() {}. Again you need to
> refer to the documentation.
>
> Second, this seems like a job for cut() not ifelse().
>
> Third, look at your code. The first statement is x$COR_LOC>=3 |
> x$COR_LOC<15.230 so everything greater than 3 will be coded as "S." That is
> probably all of your data. You probably want to use & (and) instead of |
> (or). It is not clear what you want to happen for values less than 3 but
> they will be NA (missing).
>
> Your entire ifelse() boils down to
>
> set.seed(42)
> x <- data.frame(COR_LOC=runif(100, 0, 30))
> x$ForS <- cut(x$COR_LOC, breaks=c(3, 15.23, 19.81, 25.40, Inf),
>         labels=c("S", "I1", "I2", "F"), right=FALSE)
>
> No loops, no ifelse's. Anything below 3 will
>
> -------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
>
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of Monaly Mistry
> Sent: Friday, October 17, 2014 8:27 AM
> To: r-help at r-project.org
> Subject: [R] assigning letter to a column
>
> Hi,
>
> I'm having trouble with assigning a letter to a column based on the value
> of another column.
> Since I have separate data files I've saved then into one folder and I'm
> reading them in separately into the function.
>
> The code is below.
>
> #F= fast; S= slow; I1= Intermediate score 1; I2=Intermediate score 2
> filename<-list.files(pattern="*.txt")
> filename
> corloc<- function(x){
>   x<-read.table(filename[x], sep="\t", header=TRUE) #will extract the
> relevant data file from folder 1998. ex. corloc(1) will return 1998
> breeding year data
>   x[,"ForS"]<-0 #new column
>   for (i in length(x$CORLOC)){ #this is the bit that I'm having a problem
> with since it's not assigning the appropriate letter into the "ForS" column
>   ifelse(x$COR_LOC>=3 | x$COR_LOC<15.230, ForS<-"S",
>          ifelse(x$COR_LOC>=15.230 | x$COR_LOC<19.810, ForS<-"I1",
>                 ifelse(x$COR_LOC>=19.810 | x$COR_LOC<25.540,
> FS<-"I2",ForS<-"F")))}
>   print(x)
> }
>
> I've tried some of the solutions on stackoverflow but still was
> unsuccessful.
>
> Best,
>
> Monaly.
>
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>
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> ______________________________________________
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>

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