Global variables in packages in R

by

You can use package local variables through an environment. These variables will be available to multiple functions in the package, but not (easily) accessible to the user and will not interfere with the users workspace. A quick and simple example is:

pkg.env <- new.env()

pkg.env$cur.val <- 0
pkg.env$times.changed <- 0

inc <- function(by=1) {
    pkg.env$times.changed <- pkg.env$times.changed + 1
    pkg.env$cur.val <- pkg.env$cur.val + by
    pkg.env$cur.val
}

dec <- function(by=1) {
    pkg.env$times.changed <- pkg.env$times.changed + 1
    pkg.env$cur.val <- pkg.env$cur.val - by
    pkg.env$cur.val
}

cur <- function(){
    cat('the current value is', pkg.env$cur.val, 'and it has been changed', 
        pkg.env$times.changed, 'times\n')
}

inc()
inc()
inc(5)
dec()
dec(2)
inc()
cur()

More Related Contents:

  1. Global variables in R
  2. Examples of the perils of globals in R and Stata
  3. What is the difference between assign() and
  4. Are there global variables in R Shiny?
  5. Is there a dplyr equivalent to data.table::rleid?
  6. Replace NA with previous or next value, by group, using dplyr
  7. ggplot2 – bar plot with both stack and dodge
  8. Assign multiple columns using := in data.table, by group
  9. Using the rJava package on Win7 64 bit with R
  10. `levels
  11. Getting path of an R script
  12. Subset with unique cases, based on multiple columns
  13. What are the R sorting rules of character vectors?
  14. Avoid ggplot sorting the x-axis while plotting geom_bar()
  15. How do you draw a line across a multiple-figure environment in R?
  16. Set margin size when converting from Markdown to PDF with pandoc
  17. Change row order in a matrix/dataframe
  18. Milliseconds in POSIXct Class
  19. How to access and edit Rprofile? [closed]
  20. Deleting columns from a data.frame where NA is more than 15% of the column length [duplicate]
  21. Using different scales as fill based on factor
  22. r igraph find all cycles
  23. How to read csv file in R where some values contain the percent symbol (%)
  24. How does one change the levels of a factor column in a data.table
  25. When should I use setDT() instead of data.table() to create a data.table?
  26. Remove duplicates based on 2nd column condition
  27. how can I handle vectors without knowing the type in Rcpp
  28. Adding a counter column for a set of similar rows in R [duplicate]
  29. R data table: update join
  30. Importing “csv” file with multiple-character separator to R?

Leave a Comment