Re: switch keyword

["Padhye, Nikhil S" <Nikhil.S.Padhye@uth.tmc.edu>]

Carol,

 

Not sure about switch, but

 

i.cat <- ifelse(i >= 50, 3, ifelse(i >= 20, 2, 1))

 

should do the task. Here i is your integer vector and i.cat maps those integers to the set {1,2,3}.

 

If you want i.cat to be a factor variable, enclose the right hand side _expression_ in as.factor(...).

 

Nikhil

________________________________________________

N. S. Padhye, Ph.D.

Research Assistant Professor, Biostatistician

The University of Texas Health Science Center at Houston

http://www.uth.tmc.edu

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From: s-news-owner@lists.biostat.wustl.edu [mailto:s-news-owner@lists.biostat.wustl.edu] On Behalf Of carol white
Sent: Tuesday, October 09, 2007 9:09 AM
To: s-news@lists.biostat.wustl.edu
Subject: [S] switch keyword

Hi,
I have an integer vector that I want to convert to a 
categorical vector with values 1, 2, 3. 
If the value of an element of the 
integer vector < 20, then, the value of the corresponding element in the 
categorical vector will be 1 
if the value of an element of the integer 
vector > 20 and < 50, then, the value of the corresponding element in the 
categorical vector will be 2
if the value of an element of the integer vector 
> 50, then, the value of the corresponding element in the categorical vector 
will be 3

can I do this by switch and how

look forward to your 
feedback

carol

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