[R] subset from a dataset after comparing its one column to a related vector

[David Winsemius]

On Jul 7, 2011, at 4:40 PM, Shant Ch wrote:

> Hello R users,
>
> I have two data sets like the following. Form of dataset:
>
> data:
>
>      X1       X2        X3    X4       X5
>     1902       RE        3      594        9
>      1903       RE        3     1340        7
>      1904       AA        3      760       14
>      1908       RE        4     1759       18
>      1909       EX        2      387        1
>      2901       AU        6     3116        2
>      3801       AA        1      304       29
>    3902       RE        5     2482        6
>
> I need to select rows of a data set based on the common observations  
> of X1.
> Using intersect command I got the common observations of X1 from the  
> two data
> sets as:
>
> common=c(1902, 1904, 1908, 1909, 3801).
>
> Using subset command I can select portions separately. But in  
> general if I am
> given this type of dataset - "data" with large number of rows and  
> also a list of
> X1 - "common" containing many elements, can anyone please let me  
> know  how to
> select portion of the data whose X1 values are same as common values.

subset(dfrm, x1 %in% common)

?subset

>
> If any questions let me know.
>
> Shant.
> 	[[alternative HTML version deleted]]
>
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David Winsemius, MD
West Hartford, CT