Dear R-List, 

I would like to recode my data according to quantile breaks, i.e. all data within the range of 0%-25% should get a 1, >25%-50% a 2 etc.
Is there a nice way to do this with all columns in a dataframe.

e.g.

df<- f<-data.frame(id=c("x01","x02","x03","x04","x05","x06"),a=c(1,2,3,4,5,6),b=c(2,4,6,8,10,12),c=c(1,3,9,12,15,18))

df
   id        a      b      c
1 x01     1      2      1
2 x02     2      4      3
3 x03     3      6      9
4 x04     4      8     12
5 x05     5     10     15
6 x06     6     12     18

#I can do it in very complicated way


apply(df[-1],2,quantile)
       a    b    c
0%   1.0  2.0  1.0
25%  2.2  4.5  4.5
50%  3.5  7.0 10.5
75%  4.8  9.5 14.2
100% 6.0 12.0 18.0

#then 

df$a[df$a<=2.2]<-1
...

#result should be


df.breaks

id        a        b        c
x01    1           1        1
x02    1          1        1
x03    2           2        2
x04    3           3        3
x05    4           4        4
x06    4           4        4 



But there must be a way to do it more elegantly, something like


df.breaks<- apply(df[-1],2,recode.by.quantile)

Can anyone help me with this?


Best wishes 


Alain      
	[[alternative HTML version deleted]]

