Thanks Sarah and David.
Yes, but note this:
> z <- data.frame(a=1:2,b=3:4)
> z
a b
1 1 3
2 2 4
> newdat <- 5:6
> cbind(z[,1],newdat,z[,2])
newdat
[1,] 1 5 3
[2,] 2 6 4
> cbind.data.frame(z[,1],newdat,z[,2])
z[, 1] newdat z[, 2]
1 1 5 3
2 2 6 4
Aha moment! -- You need drop=FALSE:
cbind(z[,1,drop=FALSE],newdat,z[,2,drop=FALSE])
a newdat b
1 1 5 3
2 2 6 4
So your solution does not work in general (and you may not have
intended it to); while mine does, but is blatantly clumsy. I would say
the "better" approach is merely to add the drop = FALSE option to
yours even though it is unnecessary in your simple example:
cbind(x[,1:2,drop = FALSE], newcol, x[,3:ncol(x)], drop= FALSE)
... and I would definitely count this as an R 'gotcha' . (and it has
gotcha'ed me before).
Cheers,
-- Bert
On Mon, Aug 1, 2011 at 10:37 AM, Sarah Goslee <sarah.gos...@gmail.com> wrote:
> Bert,
>
> On Mon, Aug 1, 2011 at 1:17 PM, Bert Gunter <gunter.ber...@gene.com> wrote:
>> Doesn't work -- you lose column names.
>
> But I don't lose column names:
>
>> x <- data.frame(A=1:3, B=1:3, C=1:3, D=1:3, E=1:3)
>> x
> A B C D E
> 1 1 1 1 1 1
> 2 2 2 2 2 2
> 3 3 3 3 3 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
>
> It's even possible to change names in the cbind() statement:
>
>> cbind(x[,1:2], Y=newcol, x[,3:ncol(x)])
> A B Y C D E
> 1 1 1 4 1 1 1
> 2 2 2 5 2 2 2
> 3 3 3 6 3 3 3
>
> If for some reason it isn't working for you, you might try explicitly calling
> cbind.data.frame() instead of the default cbind().
>
>
>> 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])
>
> This shouldn't be necessary, I think. What happens if you use my
> above example?
>
> Sarah
>
>
>> Cheers,
>> Bert
>>
>> On Mon, Aug 1, 2011 at 10:10 AM, Sarah Goslee <sarah.gos...@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.ban...@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
>
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