[R] Tricky filtering

[Bert Gunter]

Thanks for the nice dput example, but your specification confuses me.
What if the 2 records with largest Mean_power are not the same as the two
with largest N_records. Do you want to keep all four records? Or various
combinations of this question that would keep 3 records. And will you
always have two records on a date, or could you have just one? And if the 2
records with largest Mean_power always also have the largest N_records,
then you only need to choose the two with largest Mean_power and can ignore
the N_records, right?

Once you have answered these questions -- or someone else has a better
understanding than I -- it should be easy. It will require a loop of one
form or another, however, and therefore might take a while.

Cheers,
Bert

Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Wed, Oct 30, 2019 at 7:55 PM Cacique Samurai <caciquesamurai using gmail.com>
wrote:

> Hi all,
>
> I had a fish telemetry data with more then 11 million lines. I had some
> false records in the data, that I have to eliminate. I can solve this using
> a loop, but I think that dplyr:: filter could be faster and elegant. I just
> can't figure out how to do it.
>
> At this moment, I already summarized this raw data, and had something like
> this (dput at end of e-mail):
>
> Date Station Antenna Mean_power N_records *Action need (manually inserted)*
> 29/03/2019 ANT01 1 108 1704 Remove
> 29/03/2019 ANT01 2 94 1219 Remove
> 29/03/2019 ANT02 1 220 3029 Keep
> 29/03/2019 ANT02 2 219 2711 Keep
> 30/03/2019 ANT01 1 204 2289 Keep
> 30/03/2019 ANT01 2 172 1477 Keep
> 30/03/2019 ANT02 1 88 913 Remove
> 30/03/2019 ANT02 2 72 1080 Remove
> 30/03/2019 ETE01 AH0 87 1 Keep
>
> The problem occurs between Stations ANT01 and ANT02. In the same day, I
> have to keep the pair of records that have bigger Mean_power and more
> N_records. In this example, I have to keep records in Station ANT02 in
> 29/03 and of ANT01 and ETE01 in 30/03. If I do not have more than ANT01 and
> ANT02 in the same day, it was a simple question.
>
> I have to do this for each marked fish, that is identified by a Code supres
> here for resuming.
>
> Thanks in advanced,
>
> Raoni
>
>
> structure(list(Date = structure(c(17984, 17984, 17984, 17984, 17985, 17985,
> 17985, 17985, 17985), class = "Date"),
> Station = c("ANT01","ANT01", "ANT02", "ANT02", "ANT01", "ANT01", "ANT02",
> "ANT02","ETE01"),
> Antenna = c("1", "2", "1", "2", "1", "2", "1", "2","AH0"),
> Media_power = c(108, 94, 220, 219, 204, 172, 88, 72, 87), N_records =
> c(1704L, 1219L, 3029L, 2711L, 2289L, 1477L, 913L, 1080L, 1L)),
> row.names = c(NA, -9L), class = c("grouped_df", "tbl_df", "tbl",
> "data.frame"),
> groups = structure(list(Date = structure(c(17984, 17984, 17985, 17985,
> 17985), class = "Date"), Station = c("ANT01",
> "ANT02", "ANT01", "ANT02", "ETE01"), .rows = list(1:2, 3:4, 5:6, 7:8, 9L)),
> row.names = c(NA, -5L), class = c("tbl_df", "tbl",
> "data.frame"), .drop = TRUE))
>
>
>
>
>
>
>
> --
> Raoni Rosa Rodrigues
> Research Associate of Fish Transposition Center CTPeixes
> Universidade Federal de Minas Gerais - UFMG
> Brasil
> rodrigues.raoni using gmail.com
>
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>
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