[R] how to recode in my dataset?

[zhijie zhang]

Dear Rusers,
 My question is about "recode variables". First, i'd like to say
something about the idea of recoding:
 My dataset have three variables:type,soiltem and airtem,which means
grass type, soil temperature and air temperature. As we all known, the
change of air temperature is greater than soil temperature,so the
values in those two different temperaturemay represent different
range.
 My recoding is to recode soiltem with 0.2 intervals, and airtem with
0.5 intervals, that is:
In soiltem:0~0.2<-0.1,  0.2~0.4<-0.3, 0.4`0.6<-0.5,...etc;
In airtem:0~0.5<-0.25,  0.5~1<-0.75, 1`1.5<-1.25,...etc;
My example like this:
type<-c(1, 1, 2, 3,4,1,1,4,3,2)
soiltem<-c(19.2,18.6,19.5,19.8,19.6,20.6,19.1,18.7,22.4,21.6)
airtem<-c(19.9,20.5,21.6,25.6,22.6,21.3,23.7,21.5,24.7,24.4)
mydata<-data.frame(type,soiltem,airtem) #copy the above four arguments
to generate the dataset

mydata
   type soiltem airtem
1     1    19.2   19.9
2     1    18.6   20.5
3     2    19.5   21.6
4     3    19.8   25.6
5     4    19.6   22.6
6     1    20.6   21.3
7     1    19.1   23.7
8     4    18.7   21.5
9     3    22.4   24.7
10    2    21.6   24.4

Thanks very much!
-- 
Kind Regards,
Zhi Jie,Zhang ,PHD
Department of Epidemiology
School of Public Health
Fudan University
Tel:86-21-54237149