R help - Aug 2011 - Inserting column in between -- "better" way?

Folks:

I consider my reply below rather clumsy: One has to keep track of
index numbers other than that which is inserted and must separately
change column names. Is there as "essentially better" way to do this,
either via base R or via an R package. I leave it to you to define
"essentially better."

Thanks.

Cheers,
Bert

On Mon, Aug 1, 2011 at 10:17 AM, Bert Gunter <bgunter at gene.com>
wrote:
> Doesn't work -- you lose column names.
>
> Try this instead:
>
> yourframe[,30:51] <- cbind( newcolumn,yourframe[,30:50])
>
> Adjust column names after via:
>
> names(yourframe) [30:51] <- c(newcolname,names(yourframe[30:50])
>
> Cheers,
> Bert
>
> On Mon, Aug 1, 2011 at 10:10 AM, Sarah Goslee <sarah.goslee at
gmail.com> wrote:
>> x <- cbind(x[,1:29], newcolumn, x[,30:ncol(x)])
>>
>> On Mon, Aug 1, 2011 at 12:59 PM, Bansal, Vikas <vikas.bansal at
kcl.ac.uk> wrote:
>>> Dear all,
>>>
>>> I have a very simple question.I have data frame of 50 columns and i
want to insert a column in 30th position.But i do not want to delete that
column.Is it possible to include a column in between, so that new values are in
30th column and 30 th column is now 31st and 31st is 32nd......so on and 50th
column is 51st..?I will be very thankful to you.
>>>
>>>
>>
>>
>>
>> --
>> Sarah Goslee
>> http://www.functionaldiversity.org
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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.
>>
>
>
>
> --
> "Men by nature long to get on to the ultimate truths, and will often
> be impatient with elementary studies or fight shy of them. If it were
> possible to reach the ultimate truths without the elementary studies
> usually prefixed to them, these would not be preparatory studies but
> superfluous diversions."
>
> -- Maimonides (1135-1204)
>
> Bert Gunter
> Genentech Nonclinical Biostatistics
>


-- 
"Men by nature long to get on to the ultimate truths, and will often
be impatient with elementary studies or fight shy of them. If it were
possible to reach the ultimate truths without the elementary studies
usually prefixed to them, these would not be preparatory studies but
superfluous diversions."

-- Maimonides (1135-1204)

Bert Gunter
Genentech Nonclinical Biostatistics

Bert,

On Mon, Aug 1, 2011 at 1:27 PM, Bert Gunter <gunter.berton at gene.com>
wrote:
> Folks:
>
> I consider my reply below rather clumsy: One has to keep track of
> index numbers other than that which is inserted and must separately
> change column names. Is there as "essentially better" way to do
this,
> either via base R or via an R package. I leave it to you to define
> "essentially better."
>
Having tried your solution with sample data, I'd have to agree. :)
Your approach does mess up the column names, and also doesn't work
if x is a matrix rather than data frame. Mine, using the full cbind(), works
in both cases, preserving the column names and running even if x is
a matrix.

It could be written as a function, but since it's only one line and
really only requires knowing at what position you'd like to add
the new column, it hardly seems worth it unless it's something
to be done repeatedly.
>  x <- data.frame(A=1:3, B=1:3, C=1:3, D=1:3, E=1:3)
> newcol <- 4:6
> cbind(x[,1:2], newcol, x[,3:ncol(x)])
  A B newcol C D E
1 1 1      4 1 1 1
2 2 2      5 2 2 2
3 3 3      6 3 3 3
>
>
> x[,3:6] <- cbind(newcol, x[,3:5])
> x
  A B C D E E.1
1 1 1 4 1 1   1
2 2 2 5 2 2   2
3 3 3 6 3 3   3
>
>
> x <- data.frame(A=1:3, B=1:3, C=1:3, D=1:3, E=1:3)
> x <- as.matrix(x)
> cbind(x[,1:2], newcol, x[,3:ncol(x)])
     A B newcol C D E
[1,] 1 1      4 1 1 1
[2,] 2 2      5 2 2 2
[3,] 3 3      6 3 3 3
> x[,3:6] <- cbind(newcol, x[,3:5])
Error in x[, 3:6] <- cbind(newcol, x[, 3:5]) : subscript out of bounds

Sarah
> Thanks.
>
> Cheers,
> Bert
>
> On Mon, Aug 1, 2011 at 10:17 AM, Bert Gunter <bgunter at gene.com>
wrote:
>> Doesn't work -- you lose column names.
>>
>> Try this instead:
>>
>> yourframe[,30:51] <- cbind( newcolumn,yourframe[,30:50])
>>
>> Adjust column names after via:
>>
>> names(yourframe) [30:51] <- c(newcolname,names(yourframe[30:50])
>>
>> Cheers,
>> Bert
>>
>> On Mon, Aug 1, 2011 at 10:10 AM, Sarah Goslee <sarah.goslee at
gmail.com> wrote:
>>> x <- cbind(x[,1:29], newcolumn, x[,30:ncol(x)])
>>>
>>> On Mon, Aug 1, 2011 at 12:59 PM, Bansal, Vikas <vikas.bansal at
kcl.ac.uk> wrote:
>>>> Dear all,
>>>>
>>>> I have a very simple question.I have data frame of 50 columns
and i want to insert a column in 30th position.But i do not want to delete that
column.Is it possible to include a column in between, so that new values are in
30th column and 30 th column is now 31st and 31st is 32nd......so on and 50th
column is 51st..?I will be very thankful to you.
>>>
-- 
Sarah Goslee
http://www.functionaldiversity.org