[R] Classification

[Marc Schwartz]

On Wed, 2007-07-18 at 19:36 +0200, Ing. Michal Kneifl, Ph.D. wrote:
> Hi,
> I am also a quite new user of R and would like to ask you for help:
> I have a data frame where all columns are numeric variables. My aim is  
> to convert one columnt in factors.
> Example:
> MD
> 0.2
> 0.1
> 0.8
> 0.3
> 0.7
> 0.6
> 0.01
> 0.2
> 0.5
> 1
> 1
> 
> 
> I want to make classes:
> 0-0.2 A
> 0.21-0.4 B
> 0.41-0.6 C
> ..... and so on
> 
> So after classification I wil get:
> MD
> A
> A
> D
> B
> .
> .
> .
> and so on
> 
> Please could you give an advice to a newbie?
> Thanks a lot in advance..
> 
> Michael

See ?cut

You can then do something like:

> DF
     MD
1  0.20
2  0.10
3  0.80
4  0.30
5  0.70
6  0.60
7  0.01
8  0.20
9  0.50
10 1.00
11 1.00


> cut(DF$MD, breaks = c(seq(0, 1, .2)), labels = LETTERS[1:5])
 [1] A A D B D C A A C E E
Levels: A B C D E


HTH,

Marc Schwartz