R help - Sep 2021 - alternative to subset(dataframe, select = - column) in R

Hello,
this is a very simple question but...
what is the vector alternative to `subset(dataframe, select = - column)`?
I tried with:
```
> x = new[-ID]
Error in `[.data.frame`(new, -ID) : object 'ID' not
found
> x = new[-"ID"]
Error in -"ID" : invalid argument to unary
operator
> x = new[[-"ID"]]
Error in -"ID" : invalid argument to unary
operator
> x = new[-["ID"]]
Error: unexpected '[' in "x = new[-["
```
Thank you

x <- new[-match("ID"), names(new))]

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 Fri, Sep 24, 2021 at 7:10 AM Luigi Marongiu <marongiu.luigi at
gmail.com> wrote:
>
> Hello,
> this is a very simple question but...
> what is the vector alternative to `subset(dataframe, select = - column)`?
> I tried with:
> ```
> > x = new[-ID]
> Error in `[.data.frame`(new, -ID) : object 'ID' not found
> > x = new[-"ID"]
> Error in -"ID" : invalid argument to unary operator
> > x = new[[-"ID"]]
> Error in -"ID" : invalid argument to unary operator
> > x = new[-["ID"]]
> Error: unexpected '[' in "x = new[-["
> ```
> Thank you
>
> ______________________________________________
> R-help at 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.

The subset function

subset( new, select = -ID )

uses non-standard evaluation... it "knows" that when you write the
language symbol ID it may match to one of the column names in new, and the `-`
in the select argument will be noticed before R tries to change the sign of a
variable ID in your calling environment and cause subset to remove the
"ID" column from the returned version of new.

The vector indexing operator does none of that, so whatever indexing arguments
you specify need to be valid expressions on their own without the indexing
operator.

-ID
   You don't have a variable called ID, so its sign vanity be changed

-"ID"
   Changing the sign of a character literal is not a defined operation

-["ID"]
   Standalone brackets have no meaning in R... only can be used directly
adjacent to a vector to the right.

What you do have is the data frame `new`... and it has names, and among those
names is "ID", so...

"ID" != names( new )
   should be a logical vector with FALSE in the position corresponding to
"ID", so

new[ , "ID" != names( new ) ]

will select all of the columns other than the "ID" column.

If you want to deselect more than one column, then the %in% operator can help:

! names( new ) %in% c( "ID", "Other" )

will be a logical vector with FALSE in the corresponding positions.


On September 24, 2021 7:09:54 AM PDT, Luigi Marongiu <marongiu.luigi at
gmail.com> wrote:
>Hello,
>this is a very simple question but...
>what is the vector alternative to `subset(dataframe, select = - column)`?
>I tried with:
>```
>> x = new[-ID]
>Error in `[.data.frame`(new, -ID) : object 'ID' not found
>> x = new[-"ID"]
>Error in -"ID" : invalid argument to unary operator
>> x = new[[-"ID"]]
>Error in -"ID" : invalid argument to unary operator
>> x = new[-["ID"]]
>Error: unexpected '[' in "x = new[-["
>```
>Thank you
>
>______________________________________________
>R-help at 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.
-- 
Sent from my phone. Please excuse my brevity.

Hello,

Like this?


mtcars[names(mtcars) != "mpg"]


Hope this helps,

Rui Barradas

?s 15:09 de 24/09/21, Luigi Marongiu escreveu:
> Hello,
> this is a very simple question but...
> what is the vector alternative to `subset(dataframe, select = - column)`?
> I tried with:
> ```
>> x = new[-ID]
> Error in `[.data.frame`(new, -ID) : object 'ID' not found
>> x = new[-"ID"]
> Error in -"ID" : invalid argument to unary operator
>> x = new[[-"ID"]]
> Error in -"ID" : invalid argument to unary operator
>> x = new[-["ID"]]
> Error: unexpected '[' in "x = new[-["
> ```
> Thank you
> 
> ______________________________________________
> R-help at 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.
>