R help - Feb 2013 - recode data according to quantile breaks

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]]

Hi Alain,

The following should get you started:

apply(df[,-1], 2, function(x) cut(x, breaks = quantile(x), include.lowest TRUE,
labels = 1:4))

Check ?cut and ?apply for more information.

HTH,
Jorge.-



On Tue, Feb 19, 2013 at 9:01 PM, D. Alain <> wrote:
> 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]]
>
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
	[[alternative HTML version deleted]]

HI Alain,

Try this:
df.breaks<-data.frame(id=df[,1],sapply(df[,-1],function(x)
findInterval(x,quantile(x),rightmost.closed=TRUE)),stringsAsFactors=FALSE)
df.breaks
#?? id a b c
#1 x01 1 1 1
#2 x02 1 1 1
#3 x03 2 2 2
#4 x04 3 3 3
#5 x05 4 4 4
#6 x06 4 4 4
A.K.



----- Original Message -----
From: D. Alain <dialvac-r at yahoo.de>
To: Mailinglist R-Project <r-help at r-project.org>
Cc: 
Sent: Tuesday, February 19, 2013 5:01 AM
Subject: [R] recode data according to quantile breaks

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]]


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https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.