> On 14 Mar 2017, at 03:43 , Rolf Turner <[email protected]> wrote:
>
> On 14/03/17 14:56, Jinsong Zhao wrote:
>> Hi there,
>>
>> I happened to find the following code can generate a data frame with
>> same column name.
>>
>>> x <- data.frame(a=c(1,2,3))
>>> y <- data.frame(a=c(2,3,4))
>>> z <- cbind(x,y)
>>
>> However, in this case, one can not use the $ to extract the second
>> column, right?
>>
>> Is it possible to prevent the cbind() produce a data frame with same
>> column name?
>
> No.
>
> Why not either:
>
> (a) Just make sure the names in "x" and "y" differ?
>
> Or:
>
> (b) Change the names of "z", e.g. names(z) <- c("clyde","irving")?
>
> Or maybe names(z) <- make.unique(names(z)).
>
> You could probably write a wrapper function for cbind() to automate (b) if
> you really want to.
>
Yes, this is what it is, and I doubt anyone is likely to set out to change it.
However, it is a bit of an oddity compared to the (often undesirable) pains the
data.frame code goes through to ensure distinct _row_ names; e.g.,
> cbind(data.frame(a=1), data.frame(a=2))
a a
1 1 2
but
> rbind(data.frame(a=c(foo=1)), data.frame(a=c(foo=2)))
a
foo 1
foo1 2
-pr
--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
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