[R] Collapsing Categorical Variables

[Andrew Robinson]

Kevin,

something like ....

table(STREET)
STREET <- as.character(STREET)
STREET[as.numeric(factor(STREET)) %in% which(table(STREET) < 15)] <- "Other"
STREET <- factor(STREET)
table(STREET)


Andrew

On Thursday 26 February 2004 15:25, Ko-Kang Kevin Wang wrote:
> Hi,
>
> Suppose I have a categorical variable called STREET, and I have 30
> levels for it (i.e. 30 different streets).  I want to find all those
> streets with only 15 observations or below then collapse them into a
> level called OTHER.  Is there a quick way, other than using a for()
> loop, to do it?  Currently what I'm doing is something like:
>   ### Collapse STREET (those < 15)
>   st <- c()
>   STREET <- as.vector(STREET)
>   for(i in 1:length(STREET)) {
>     if(STREET[i] == "BOYNE AVE" ||
>        STREET[i] == "CHAPEL ST" ||
>        STREET[i] == "CONE PL" ||
>        STREET[i] == "LACEBARK LANE" ||
>        STREET[i] == "PRUDHOE LANE" ||
>        STREET[i] == "VIRGIL PL" ||
>        STREET[i] == "WILMOT ST" ) st[i] <- "Other"
>     else st[i] <- STREET[i]
>   }
>
> But I'm sure there is a better way....
>
> Kevin
>
> --------------------------------------------
> Ko-Kang Kevin Wang, MSc(Hon)
> Statistics Workshops Co-ordinator
> Student Learning Centre
> University of Auckland
> New Zealand
>
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