Hi Steven and Peter,
I apologise for not providing the code for the sample

I now realise what I need may be a bit tricky... 
my dataframe has hundreds of IDs in which case Steven's solution will not be 
optimum

Peter's solution seems best, but how do I reverse this and use it to select the 
dataframe rows which do not contain particular IDs say for example IDs 2 and 5 
in this case.

Thanks again for your time
Rith




________________________________
From: Peter Ehlers <ehl...@ucalgary.ca>
To: steven mosher <mosherste...@gmail.com>

org>
Sent: Wed, December 15, 2010 3:26:14 AM
Subject: Re: [R] selecting certain rows from data frame

On 2010-12-14 23:57, steven mosher wrote:
> Hi,
> Next time give folks code to produce a toy sample of your problem
>
>  DF<-data.frame(ID=rep(1:5,each=3),Data=rnorm(15),Stuff=seq(1:15))
>    DF
>    ID      Data Stuff
> 1  1  2.0628225    1
> 2  1  0.6599165    2
> 3  1  0.5672595    3
> 4  2 -0.5308823    4
> 5  2 -0.5358471    5
> 6  2 -0.1414992    6
> 7  3 -0.1679643    7
> 8  3  0.9220922    8
> 9  3  0.8863018    9
> 10  4 -0.7255916    10
> 11  4 -1.2446753    11
> 12  4  0.8165567    12
> 13  5  0.0925008    13
> 14  5 -0.8534803    14
> 15  5 -0.6535016    15
>
> # now I want to select rows where ID = 2 or 5
> # Assign DF2 to those elements of DF where the ID variable=2 or 5
>
>  DF2<- DF[which(DF$ID==2 | DF$ID==5), ]

Or use subset():

  DF2 <- subset(DF, ID %in% c(2,5))

Peter Ehlers

>  DF2
>    ID      Data Stuff
> 4  2 -0.5308823    4
> 5  2 -0.5358471    5
> 6  2 -0.1414992    6
> 13  5  0.0925008    13
> 14  5 -0.8534803    14
> 15  5 -0.6535016    15
>

>
>> Hi,
>> if I have a dataframe such that
>>
>> ID Time  Earn
>> 1        1        10
>> 1        2        50
>> 1        3        68
>> 2        1        40
>> 2        2        78
>> 2        4      88
>> 3        1        50
>> 3        2        60
>> 3        3        98
>> 4        1        33
>> 4        2        48
>> 4        4      58
>> .....
>> ....
>> .....
>>
>> Now if I have to select the all the rows from the data frame which does not
>> include rows with certain IDs, say for example (prime) ID == 2&  3, how do
>> I do
>> it
>>
>>
>> Thanks
>>
>> Rith
>>



      
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