# [R] Selecting elements

Silvano Cesar da Costa @||v@no @end|ng |rom ue|@br
Fri Aug 20 21:27:50 CEST 2021

```Hi, thanks you for the answer.
Sorry English is not my native language.

But you got it right.
> As C is first and fourth biggest value, you follow third option and
select 3 highest A, 3B 2C and 2D?

I must select the 10 (not 15) highest values, but which follow a certain
order:
3A - 3B - 2C - 2D     or
2A - 5B - 0C - 3D     or
3A - 3B - 2C - 2D

I'll put the example in Excel for a better understanding (with 20 elements
only).
I must select 10 elements (the highest values of variable Var.2), which fit
one of the 3 options above.

Number Position Var.1 Var.2
1 27 C 40
2 30 B 39 Selected:
3 5 A 38 Number Position Var.1 Var.2
4 16 D 37 1 27 C 40
5 23 C 36 2 30 B 39   3A - 3B - 2C - 2D
6 13 A 35 3 5 A 38
7 20 D 34 4 16 D 37 3A - 3B - 1C - 3D
8 12 D 33 5 23 C 36
9 9 A 32 6 13 A 35 2A - 5B - 0C - 3D
10 1 A 31 7 20 D 34
11 21 A 30 10 9 A 32
12 35 C 29 13 14 B 28
13 14 B 28 17 6 B 25
14 8 D 27
15 7 C 26
16 6 B 25
17 40 D 24
18 26 B 23
19 29 A 22
20 31 C 21

Second option (other data set):

Number Position Var.1 Var.2
1 36 D 20
2 11 B 19 Selected:
3 39 A 18 Number Position Var.1 Var.2
4 24 D 17 1 36 D 20
5 34 B 16 2 11 B 19   3A - 3B - 2C - 2D
6 2 B 15 3 39 A 18
7 3 A 14 4 24 D 17   3A - 3B - 1C - 3D
8 32 D 13 5 34 B 16
9 28 D 12 6 2 B 15 2A - 5B - 0C - 3D
10 25 A 11 7 3 A 14
11 19 B 10 8 32 D 13
12 15 B 9 9 25 A 11
13 17 A 8 10 18 C 7
14 18 C 7
15 38 B 6
16 10 B 5
17 22 B 4
18 4 D 3
19 33 A 2
20 37 A 1

How to make the selection of these 10 elements that fit one of the 3
options using R?

Thanks,

Prof. Dr. Silvano Cesar da Costa
Universidade Estadual de Londrina
Centro de Ciências Exatas
Departamento de Estatística

Fone: (43) 3371-4346

Em sex., 20 de ago. de 2021 às 03:28, PIKAL Petr <petr.pikal using precheza.cz>
escreveu:

> Hallo
>
> I am confused, maybe others know what do you want but could you be more
> specific?
>
> Let say you have such data
> set.seed(123)
> Var.1 = rep(LETTERS[1:4], 10)
> Var.2 = sample(1:40, replace=FALSE)
> data = data.frame(Var.1, Var.2)
>
> What should be the desired outcome?
>
> You can sort
> data <- data[order(data\$Var.2, decreasing=TRUE), ]
> and split the data
> > split(data\$Var.2, data\$Var.1)
> \$A
>  [1] 38 35 32 31 30 22 11  8  2  1
>
> \$B
>  [1] 39 28 25 23 16 15  7  6  5  4
>
> \$C
>  [1] 40 36 29 26 21 19 18 14 10  9
>
> \$D
>  [1] 37 34 33 27 24 20 17 13 12  3
>
> T inspect highest values. But here I am lost. As C is first and fourth
> biggest value, you follow third option and select 3 highest A, 3B 2C and 2D?
>
> Or I do not understand at all what you really want to achieve.
>
> Cheers
> Petr
>
> > -----Original Message-----
> > From: R-help <r-help-bounces using r-project.org> On Behalf Of Silvano Cesar
> da
> > Costa
> > Sent: Thursday, August 19, 2021 10:40 PM
> > To: r-help using r-project.org
> > Subject: [R] Selecting elements
> >
> > Hi,
> >
> > I need to select 15 elements, always considering the highest values
> > (descending order) but obeying the following configuration:
> >
> > 3A - 4B - 0C - 3D or
> > 2A - 5B - 0C - 3D or
> > 3A - 3B - 2C - 2D
> >
> > If I have, for example, 5 A elements as the highest values, I can only
> choose
> > (first and third choice) or 2 (second choice) elements.
> >
> > how to make this selection?
> >
> >
> > library(dplyr)
> >
> > Var.1 = rep(LETTERS[1:4], 10)
> > Var.2 = sample(1:40, replace=FALSE)
> >
> > data = data.frame(Var.1, Var.2)
> > (data = data[order(data\$Var.2, decreasing=TRUE), ])
> >
> > Elements = data %>%
> >   arrange(desc(Var.2))
> >
> > Thanks,
> >
> > Prof. Dr. Silvano Cesar da Costa
> > Universidade Estadual de Londrina
> > Centro de Ciências Exatas
> > Departamento de Estatística
> >
> > Fone: (43) 3371-4346
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
>

[[alternative HTML version deleted]]

```

More information about the R-help mailing list