R CMD methods and ggplot2 advice

Dear Rolf,

utils::globalVariables() seems to work package wide. I prefer to ignore
these variable only within the function in which I explicitly define them.
If I use one of those variables in another function in which I haven't
declared them as global, then I want R CMD check to give me a NOTE.

Best regards,

ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium

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what the experiment died of. ~ Sir Ronald Aylmer Fisher
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ensure that a reasonable answer can be extracted from a given body of data.
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2015-05-28 11:28 GMT+02:00 Rolf Turner <r.turner at auckland.ac.nz>:

On 27/05/15 23:37, Thierry Onkelinx wrote:

Dear Glenn,

Suppose this function

test <- function(df){
   ggplot(df, aes(x = gp, y = y)) + geom_point()
}

Then R CMD check will consider gp and y as global variables since they are
undefined. Because R CMD check cannot detect that gp and y will be
extracted from df by ggplot2.

Possible workarounds

# now gp and y are defined within the function. ggplot2 still looks for gp
and y in df.
test <- function(df){
   gp <- NULL
   y <- NULL
   ggplot(df, aes(x = gp, y = y)) + geom_point()
}

# now "gp" and "y" are strings and hence defined
test <- function(df){
   ggplot(df, aes_string(x = "gp", y = "y")) + geom_point()
}

<SNIP>

Why not use utils::globalVariables?

cheers,

Rolf Turner

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