[R] Add column to dataframe based on code in other column

[MacQueen, Don]

Assuming your data frame of users is named 'users',
and using your mapping vectors:

 users$regions <- ''
 users$regions[ users$State_Code) %in% NorthEast ] <- 'NorthEast'

and repeat for the other regions


Or, if you put your mappings in a data frame then it is
as simple as

  merge(yourdataframe, regions)

(assuming the data frame of mappings is named 'regions')


The regions data frame should have two columns and 50 rows
The two columns contain the state codes and their
respective regions.

How you get that data frame of regions could vary;
here's an example using your vectors, but just two
of the regions:

regions <- data.frame(
  region= c( rep('NorthEast',length(NorthEast)),
             rep('MidWest,length(MidWest))
           ),
  State_Code=c(NorthEast,Midwest)
  )

Note that this is untested. For example,
I could easily have mismatched parentheses.

The whole thing could also be done using match(),
without creating the dataframe of regions.


-Don

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 8/8/13 2:33 AM, "Dark" <info at software-solutions.nl> wrote:

>Hi all,
>
>I have a dataframe of users which contain US-state codes.
>Now I want to add a column named REGION based on the state code. I have
>already done a mapping:
>
>NorthEast <- c(07, 20, 22, 30, 31, 33, 39, 41, 47)
>MidWest <- c(14, 15, 16, 17, 23, 24, 26, 28, 35, 36, 43, 52)
>South <- c(01, 04, 08, 09, 10, 11, 18, 19, 21, 25, 34, 37, 42, 44, 45, 49,
>51)
>West <- c(02, 03, 05, 06, 12, 13, 27, 29, 32, 38, 46, 50, 53)
>Other <- c(40, 48, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 94,
>98, 99)
>
>So for example:
>Name    State_Code
>Tom       20
>Harry     56
>Ben         05
>Sally       04
>
>Should become like:
>So for example:
>Name    State_Code REGION
>Tom       20                   NorthEast
>Harry     56                   Other
>Ben         05                  West
>Sally       04                   South
>
>Could anyone help me with a clever statement?
>
>
>
>--
>View this message in context:
>http://r.789695.n4.nabble.com/Add-column-to-dataframe-based-on-code-in-oth
>er-column-tp4673335.html
>Sent from the R help mailing list archive at Nabble.com.
>
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