[R-sig-eco] Subset dataframe

[ONKELINX, Thierry]

Something like this?

cpueData[ave(cpueData$LRVS_cpue, cpueData$outingID, FUN = max) == cpueData$LRVS_cpue, ]

untest since you didn't provide some easy to copy-and-paste dataset. Use the output of dput(sample.data.frame) to provide sample data

ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium
+ 32 2 525 02 51
+ 32 54 43 61 85
Thierry.Onkelinx at inbo.be
www.inbo.be

To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

-----Oorspronkelijk bericht-----
Van: r-sig-ecology-bounces at r-project.org [mailto:r-sig-ecology-bounces at r-project.org] Namens Jade Maggs
Verzonden: dinsdag 16 april 2013 14:13
Aan: r-sig-ecology at r-project.org
Onderwerp: [R-sig-eco] Subset dataframe

Hi list, I need to subset the dataframe below by selecting rows with maximum LRVS_cpue values for each outing_ID. For example, where outing_ID == 51801, the new dataframe should have only one row with LRVS_cpue = 0.5. LRVS_cpue in all other rows should remain as 0. I have over 650 000 rows, so looping is very slow.



I have tried: >cpueData1 <-
data.frame(unique(cpueData[max(cpueData$LRVS_cpue),])) but this does not work.



Any help would be greatly appreciated.






patrol_ID

outing_ID

num_anglers

hours_fish

ang_hours

LRVS_cpue


51709

51795

2

3.5

7

0


51709

51796

1

0.5

0.5

0


51709

51797

1

1

1

0


51709

51798

1

2

2

0


51709

51799

5

5.5

27.5

0


51709

51800

1

3

3

0


51709

51801

2

1

2

0


51709

51801

2

1

2

0.5


51709

51802

1

1.5

1.5

0


51709

51803

3

1

3

0


51709

51804

4

1

4

0



JADE MAGGS

Assistant Scientist


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