Thanks!
Why have to add “x” at the end of function, which was what I missed.
> On Jun 18, 2018, at 2:53 PM, Bert Gunter <bgunter.4...@gmail.com> wrote:
>
> It depends on whether you wish to refer to the column to be logged by name or
> index.
>
> Reprex:
>
> set.seed(1234)
> dat <- lapply(1:3, function(i)data.frame(a = runif(5), b = sample(letters,5)))
>
> ## by numerical index of column
> d <- lapply(dat,function(x){x[,"logged"]<- log10(x[,1]); x})
>
> ## by name of column
> dd <- lapply(dat,function(x){x[,"logged"]<- log10(x[,"a"]); x})
>
> There are also slight variations on how you can do the "[" indexing that
> others may post.
> Note that you have to return the modified data frame in the function.
>
> Cheers,
> Bert
>
>
>
>
>
>
> 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 Mon, Jun 18, 2018 at 1:46 PM, Honkit Wong <stephe...@gmail.com> wrote:
>> Dear R community,
>> I have a question seems very simple but have trouble to do it.
>> I have a list which stores many data frames. Now, I want to perform log10 on
>> one column in each data frame in the list and save the value as a new column
>> back to the original data frame in the list. How do I quickly do that with
>> lapply function ?
>>
>> Many thanks.
>> ______________________________________________
>> R-help@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.
>
[[alternative HTML version deleted]]
______________________________________________
R-help@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.
