R help - Jul 2007 - select row

Hi all,
I have a little problem selecting some rows from a data.frame.
I'd like to select the rows where a determinated column take a
partivolar value.

For example:
tab
          id       x       y
1    24-2005 1621814 4834991
2    24-2005 1621856 4834907
3    24-2005 1621763 4834956
4   25-2006 1622330 4835189
5   25-2006 1622533 4834834
6   25-2006 1622535 4834909
7   25-2006 1622543 4834803
8   28-2005 1622798 4835043
9   28-2005 1622299 4835129

I'd like to select the row where id=25-2006

I searched on the search of the R site but I did'nt find anything of simple.
Can someone help me?

Thank you very much
Leonardo

Assuming that id is a character.

tab[tab$id == "25-2006", ]

Cheers,

Thierry
------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium
tel. + 32 54/436 185
Thierry.Onkelinx op inbo.be
www.inbo.be 

Do not put your faith in what statistics say until you have carefully
considered what they do not say.  ~William W. Watt
A statistical analysis, properly conducted, is a delicate dissection of
uncertainties, a surgery of suppositions. ~M.J.Moroney

 
> -----Oorspronkelijk bericht-----
> Van: r-help-bounces op stat.math.ethz.ch 
> [mailto:r-help-bounces op stat.math.ethz.ch] Namens Leonardo Lami
> Verzonden: dinsdag 3 juli 2007 11:34
> Aan: r-help op stat.math.ethz.ch
> Onderwerp: [R] select row
> 
> Hi all,
> I have a little problem selecting some rows from a data.frame.
> I'd like to select the rows where a determinated column take 
> a partivolar value.
> 
> For example:
> tab
>           id       x       y
> 1    24-2005 1621814 4834991
> 2    24-2005 1621856 4834907
> 3    24-2005 1621763 4834956
> 4   25-2006 1622330 4835189
> 5   25-2006 1622533 4834834
> 6   25-2006 1622535 4834909
> 7   25-2006 1622543 4834803
> 8   28-2005 1622798 4835043
> 9   28-2005 1622299 4835129
> 
> I'd like to select the row where id=25-2006
> 
> I searched on the search of the R site but I did'nt find 
> anything of simple.
> Can someone help me?
> 
> Thank you very much
> Leonardo
> 
> ______________________________________________
> R-help op stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

?which

Use it to find the rows and then extract the rows 

 selection  <- mydata[which(mydata$id=="25-2006"), ]

 should work.

--- Leonardo Lami <lami at faunalia.it> wrote:
> Hi all,
> I have a little problem selecting some rows from a
> data.frame.
> I'd like to select the rows where a determinated
> column take a
> partivolar value.
> 
> For example:
> tab
>           id       x       y
> 1    24-2005 1621814 4834991
> 2    24-2005 1621856 4834907
> 3    24-2005 1621763 4834956
> 4   25-2006 1622330 4835189
> 5   25-2006 1622533 4834834
> 6   25-2006 1622535 4834909
> 7   25-2006 1622543 4834803
> 8   28-2005 1622798 4835043
> 9   28-2005 1622299 4835129
> 
> I'd like to select the row where id=25-2006
> 
> I searched on the search of the R site but I did'nt
> find anything of simple.
> Can someone help me?
> 
> Thank you very much
> Leonardo
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained,
> reproducible code.
>