[R] changing column labels for data frames inside a list

[Sven E. Templer]

On 30 March 2015 at 16:47, Sarah Goslee <sarah.goslee at gmail.com> wrote:

> colnames(e) <- paste0('pop',1:12)
>
> isn't a function and doesn't return anything.
>

But
function(e){colnames(e) <- paste0('pop', 1:2)}
is a function and it returns something (the last evaluated expression! -
here the paste0 return):

> mylist2 <- lapply(mylist, function(e){colnames(e) <- paste0('pop', 1:2)})
> mylist2
[[1]]
[1] "pop1" "pop2"

[[2]]
[1] "pop1" "pop2"

[[3]]
[1] "pop1" "pop2"

 from ?return:

If the end of a function is reached without calling return, the value of
the last evaluated expression is returned.

>
> > mylist <- list(
> + data.frame(a = runif(10), b = runif(10)),
> + data.frame(c = runif(10), d = runif(10)),
> + data.frame(e = runif(10), f = runif(10)))
> > mylist2 <- lapply(mylist, function(e){colnames(e) <- paste0('pop', 1:2);
> e})
> > colnames(mylist2[[1]])
> [1] "pop1" "pop2"
>
> Sarah
>
> On Mon, Mar 30, 2015 at 9:54 AM, Vikram Chhatre
> <crypticlineage at gmail.com> wrote:
> >> summary(mygenfreqt)
> >                   Length Class  Mode
> > dat1.str 59220  -none- numeric
> > dat2.str 59220  -none- numeric
> > dat3.str 59220  -none- numeric
> >
> >> head(mylist[[1]])
> >            1     2     3     4     5     6     7     8     9    10    11
> >  12
> > L0001.1 0.60 0.500 0.325 0.675 0.600 0.500 0.500 0.375 0.550 0.475 0.350
> > 0.275
> > L0001.2 0.40 0.500 0.675 0.325 0.400 0.500 0.500 0.625 0.450 0.525 0.650
> > 0.725
> >
> > I want to change 1:12 to pop1:pop12
> >
> > mylist<- lapply(mylist, function(e) colnames(e) <- paste0('pop',1:12))
> >
> > What this is doing is replacing the data frames with just names
> > pop1:pop12.  I just want to replace the column labels.
> >
> > Thanks for any suggestions.
> >
>
> --
> Sarah Goslee
> http://www.functionaldiversity.org
>
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