Thanks Gabor, I like your solution that splits the args into separate columns,
in turn making the sprintf() call more interpretable .
Cheers.
Mateo.
--
Mateo Obregón
On Friday, 29 December 2023 18:45:06 GMT Gabor Grothendieck wrote:
> If the question is how to accomplish this as opposed to how to use eval
> then we can do it without eval like this provided we can assume that words
> contains three %s .
>
> library(dplyr)
> library(tidyr)
> df <- tibble(words=c("%s plus %s equals
> %s"),args=c("1,1,2","2,2,4","3,3,6"))
>
> df |>
> separate_wider_delim(args, ",", names = c("a", "b", "c")) |>
> mutate(combined = sprintf(words, a, b, c))
> ## # A tibble: 3 × 5
> ## words a b c combined
> ## <chr> <chr> <chr> <chr> <chr>
> ## 1 %s plus %s equals %s 1 1 2 1 plus 1 equals 2
> ## 2 %s plus %s equals %s 2 2 4 2 plus 2 equals 4
> ## 3 %s plus %s equals %s 3 3 6 3 plus 3 equals 6
>
> On Fri, Dec 29, 2023 at 9:14 AM Mateo Obregón <obregonma...@gmail.com>
wrote:
> > Hi all-
> >
> > Looking through stackoverflow for R string combining examples, I found the
> > following from 3 years ago:
> >
> > <https://stackoverflow.com/questions/63881854/how-to-format-strings-using->
> > > values-from-other-column-in-r>
> >
> > The top answer suggests to use eval(parse(sprintf())). I tried the
> > suggestion and it did not return the expected combines strings. I thought
> > that this might be an issue with some leftover values being reused, so I
> > explicitly eval()>
> > with a new.env():
> > > library(dplyr)
> > > df <- tibble(words=c("%s plus %s equals %s"),
> >
> > args=c("1,1,2","2,2,4","3,3,6"))
> >
> > > df |> mutate(combined = eval(parse(text=sprintf("sprintf('%s', %s)",
> > > words,
> >
> > args)), envir=new.env()))
> >
> > # A tibble: 3 × 3
> >
> > words args combined
> > <chr> <chr> <chr>
> >
> > 1 %s plus %s equals %s 1,1,2 3 plus 3 equals 6
> > 2 %s plus %s equals %s 2,2,4 3 plus 3 equals 6
> > 3 %s plus %s equals %s 3,3,6 3 plus 3 equals 6
> >
> > The `combined` is not what I was expecting, as the same last eval() is
> > returned for all three rows.
> >
> > Am I missing something? What has changed in the past three years?
> >
> > Mateo.
> > --
> > Mateo Obregón
> >
> > ______________________________________________
> > R-devel@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
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