[R] select() columns using their positions

[Rui Barradas]

Hello,

It is also possible to select by vectors of indices (as opposed to a 
vector):
top_n is just to not clutter the display.


library(dplyr)

data(iris)

iris %>% select(1, 3, 4) %>% top_n(5)
iris %>% select(c(1, 3), 4) %>% top_n(5)


Hope this helps,

Rui Barradas


Às 10:05 de 20/08/20, Ivan Calandra escreveu:
> OK, my bad... I'm sure I had tried it and it didn't work, but I guess
> the error was somewhere else...
> 
> Thank you!
> Ivan
> 
> --
> Dr. Ivan Calandra
> TraCEr, laboratory for Traceology and Controlled Experiments
> MONREPOS Archaeological Research Centre and
> Museum for Human Behavioural Evolution
> Schloss Monrepos
> 56567 Neuwied, Germany
> +49 (0) 2631 9772-243
> https://www.researchgate.net/profile/Ivan_Calandra
> 
> On 20/08/2020 11:03, Jeff Newmiller wrote:
>> Did you try it?
>>
>> mydata %>%
>>    select( c( 1, 2, 4 ) )
>>
>> On August 20, 2020 1:41:13 AM PDT, Ivan Calandra <calandra using rgzm.de> wrote:
>>> Dear useRs,
>>>
>>> I'm still trying to learn tidyverse syntax.
>>>
>>> I would like to select() columns based on their positions/indices, but
>>> I
>>> cannot find a way to do that (I've seen a lot about doing that for
>>> rows,
>>> but I could not find anything for columns). I thought it would be
>>> obvious, but I cannot find it.
>>>
>>> Basically, I am looking for something like:
>>> mydata %>%
>>>    select( vector_of_indices )
>>> I know that the pipe is useless here, but there are more steps in my
>>> real code.
>>>
>>> The helper num_range() works only when headers contains the positions
>>> (e.g. "x1, x2...").
>>>
>>> Of course, it's easy using "[", but I expected it would be possible
>>> with
>>> select() as well; it would make the code more readable than:
>>> mydata %>%
>>>    .[ vector_of_indices ]
>>>
>>> Thank you for your help.
>>> Ivan
> 
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