Hi,
Didn't bother to run the code because someone else said it might do what
you intended, and also your problem description was complete unto itself.
The issue is that R copies on change. You are thinking like you have a
reference, which you do not. That is not very R like in style, but it
certainly can be accomplished if you want via change of input class (See
new.env()). A typical R style would be to make the modifications to the
input argument, return it, and then assign it back to the input object.
e.g.
test = myFunction(test)
If you really have some reason to want to change the data.frame in a
function without re-assigning it then check out data.table, which has that
as a side effect of how it operates.
Thanks,
On Sun, Nov 13, 2016 at 2:09 PM, Bernardo Doré <berd...@gmail.com> wrote:
> Hello list,
>
> my first post but I've been using this list as a help source for a while.
> Couldn't live without it.
>
> I am writing a function that takes a dataframe as an argument and in the
> end I intend to assign the result of some computation back to the
> dataframe. This is what I have so far:
>
> myFunction <- function(x){
> y <- x[1,1]
> z <- strsplit(as.character(y), split = " ")
> if(length(z[[1]] > 1)){
> predictedWord <- z[[1]][length(z[[1]])]
> z <- z[[1]][-c(length(z[[1]]))]
> z <- paste(z, collapse = " ")
> }
> x[1,1] <- z
> }
>
> And lets say I create my dataframe like this:
> test <- data.frame(var1=c("a","b","c"),var2=c("d","e","f"))
>
> and then call
> myFunction(test)
>
> The problem is when I assign x[1,1] to y in the first operation inside the
> function, x becomes a dataframe inside the function scope and loses the
> reference to the dataframe "test" passed as argument. In the end when I
> assign z to what should be row 1 and column 1 of the "test" dataframe, it
> assigns to x inside the function scope and no modification is made on
> "test".
>
> I hope the problem statement is clear.
>
> Thank you,
>
> Bernardo Doré
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
[[alternative HTML version deleted]]
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R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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