[R] Columnwise Alternate Subsetting of a Data Frame

[Charles C. Berry]

See

 	?split

help.search() is (or should be) your friend.

HTH,

Chuck

On Mon, 23 Jun 2008, Gundala Viswanath wrote:

> Hi,
>
> Given this data frame:
>
>> print(repo.dat)
>                               V1             V2      V3      V4
>      V5   .... (can be more)
> 1      1007_s_at   DDR1  2865.1  2901.3  1978.3   300.2
> 2       1053_at      RFC2   103.6    81.6   108.0          101.3
>
> I want to split them into two data frames yielding:
>
>                               V1             V2         V3      ... etc
> 1      1007_s_at   DDR1  2865.1    1978.3
> 2       1053_at      RFC2   103.6      108.0
>
> (V2 and V3 is obtain from V2 and V4 of original repo.dat)
>
> and
>
>                               V1                V2           V3   ...etc
> 1      1007_s_at   DDR1    2901.3     300.2
> 2       1053_at      RFC2      81.6        101.3
>
>
> (V2 and V3 is obtain from V3 and V5 of original repo.dat)
>
> In principle what we desire to do is to:
> 1. Given original data frame with V1, V2, V3, V4....
> 2. Split the data frame into two based on V2,V4,V6 ... (even) and V3,
> V5, V7 ..(odd) in the original data frame
> 3. Meanwhile keep row names and V1 in two newly formed data frames.
>
> Is there a compact way to do it?
>
> - Gundala Viswanath
> Jakarta - Indonesia
>
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> and provide commented, minimal, self-contained, reproducible code.
>

Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901