R help - Apr 2006 - deleting rows with the same ID if any meet a condition

Hello R masters,

This request is being made after searching through archive mailing list.

I have a "many" table in a medical application where each injury a
person suffers is recorded as a separate row.  In my toy example below it means
respondent #1 had three injuries and so on.

If x2 equal 2 then I want to delete all the rows for that person from the
dataframe--see Before and After below.  I have thought about using match to
first identify the IDs that have a 2 in x2 and then in a second step delete all
rows that have matching IDs with this subset, but I have not been able to get it
to work.  Any help would be much appreciated.


Before
x1 <- c(1,1,1,2,2,3,3,3)
x2 <- c(2,3,3,1,1,4,4,2)
x3 <- data.frame(x1,x2)
> x3
  x1 x2
1  1  2
2  1  3
3  1  3
4  2  1
5  2  1
6  3  4
7  3  4
8  3  2

After
  x1 x2
1  2  1
2  2  1

R 2.3.0
Windows XP

Thanks!
Greg Blevins
The Market Solutions Group


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[gblevins]
>If x2 equal 2 then I want to delete all the rows for that person from 
>the dataframe--see Before and After below.
>Before
>x1 <- c(1,1,1,2,2,3,3,3)
>x2 <- c(2,3,3,1,1,4,4,2)
>x3 <- data.frame(x1,x2)
>> x3
>  x1 x2
>1  1  2
>2  1  3
>3  1  3
>4  2  1
>5  2  1
>6  3  4
>7  3  4
>8  3  2
>After
>  x1 x2
>1  2  1
>2  2  1
You might try:

  subset(x3, !x1 %in% x1[which(x2==2)])

-- 
Fran?ois Pinard   http://pinard.progiciels-bpi.ca