[R] Re-grouping data in R

[David L Carlson]

Your first command erases all the data in that column:

dat$final_purchase_amount<- NA

so when you refer to it later, it consists of only NAs.

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Abraham Mathew
> Sent: Tuesday, August 07, 2012 1:57 PM
> To: r-help at r-project.org
> Subject: [R] Re-grouping data in R
> 
> I have a data frame with a column of values that I want to bucket
> (group)
> into specific levels.
> 
> > str(dat)'data.frame':	3678 obs. of  39 variables:
>  $ id                          : int  23 76 129 156 166 180 200 214 296
> 344 ...
>  $ final_purchase_amount       : Factor w/ 32 levels
> "\\N","1082","1109",..: 1 1 1 1 1 1 1 1 1 1 ...
> 
> 
> So I ran the following to produce new levels, one for values from 100
> to 400, 401 to 1000, and 1001+.
> 
> 
> dat$final_purchase_amount<- NA
> dat$final_purchase_amount[dat$final_purchase_amount %in%
> levels(dat$final_purchase_amount)[c(8,9,11,12,13,15,16,17,18,19,20,21)]
> ]
> <- "100 to 400"
> dat$final_purchase_amount[dat$final_purchase_amount %in%
> levels(dat$final_purchase_amount)[c(22,23,24,25,26,27,28,29,30,31,32)]]
> <- "401 to 1000"
> dat$final_purchase_amount[dat$final_purchase_amount %in%
> levels(dat$final_purchase_amount)[c(2,3,4,5,6,7,10,14)]] <- "1001 +"
> dat$final_purchase_amount <- factor(dat$final_purchase_amount)
> levels(dat$final_purchase_amount)
> table(dat$final_purchase_amount)
> 
> 
> 
> However, this doesn't seem to produce any levels and returns the
> following.
> 
> 
> > levels(dat$final_purchase_amount)character(0)
> 
> 
> 
> Can anyone point to what I'm doing wrong.
> 
> 
> 
> Thanks!
> 
> 
> --
> *Abraham Mathew
> Statistical Analyst
> www.amathew.com
> 720-648-0108
> @abmathewks*
> 
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> 
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