Use new select helpers

[DominiqueMakowski]

Once insight+DW hit cran, we should implement better selection tools in correlation

correlation/R/correlation.R

Lines 303 to 304 in c7829ff

	data2 <- if (!is.null(select2)) data[select2]
	data <- data[select]

[turbanisch]

Are you referring to something like tidyverse's data masking functionality/tidy-select? That's what's on my wishlist too! Especially if we could then create varibles on the fly like so:

iris %>% 
  corrrelation(
    select = log(Petal.Width),
    select2 = log(Sepal.Length)
  )