[R] filtering number of values in a data frame

[Simon Pickett]

I think you can then use merge() to merge them back together

n<- merge(n, df, by.x = c("m.values"), by.y = c("Start"), all.x = F, all.y = 
F)

also see ?aggregate for a more efficient solution.

HTH, Si.

----- Original Message ----- 
From: "Schönemann, Rene" <RSchoenemann at Railways.TU-Berlin.de>
To: <R-help at r-project.org>
Sent: Thursday, June 18, 2009 1:37 PM
Subject: [R] filtering number of values in a data frame


> Dear list,
>
> given is the following data frame df():
>
>        Number           Place               Start                 End
> 1 218024740787 HHO     5   263 2008-01-02 00:21:14 2008-01-03 15:25:16
> 2 218024740787 HHO     5   263 2008-01-02 00:21:14 2008-01-02 00:21:14
> 3 318039091794 HHO     5   263 2008-01-02 00:21:14 2008-01-02 13:22:54
> 4 318039091794 HHO     5   263 2008-01-02 00:21:14 2008-01-02 00:21:14
> 5 318039379900 HHO     1   104 2008-01-02 06:45:01 2008-01-02 09:15:23
>
> Now, I want to count the number of equal values of column "Start" but I 
> also want the other columns to be preserved.
>
> Using:
>
> rle(as.character(df$Start)) -> m
> n <- data.frame(m$values, m$lengths)
>
> produces a list of items according to their frequency of the Start point:
>
>              m.values m.lengths
> 1 2008-01-02 00:21:14         4
> 2 2008-01-02 06:45:01         1
>
>
> I want now also other columns to be in this new data frame. It should look 
> like that:
>
>          Number           Place           m.values  m.lengths
> 1 218024740787 HHO     5   263 2008-01-02 00:21:14         4
> 2 318039379900 HHO     1   104 2008-01-02 06:45:01         1
>
>
> Does anybody can help me with this?
>
> Thanking you in advance!
>
> René Schönemann
>
> -- 
> ______________________________________________________
>
> Technische Universität Berlin
> Institut für Land- und Seeverkehr
> Fachgebiet Schienenfahrwege und Bahnbetrieb
> Prof. Dr.-Ing. habil. Jürgen Siegmann
>
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>
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>
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> ______________________________________________________
>
> Dipl.-Verk.wirtsch. René Schönemann
> - Wissenschaftlicher Mitarbeiter -
>
> Telefon     +49 (0)30 314 - 22 710
> Telefax     +49 (0)30 314 - 25 530
>
> E-Mail      RSchoenemann at railways.tu-berlin.de
> ______________________________________________________
>
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