code_to_function {drake}

Turn a script into a function.

Description

code_to_function() is a quick (and very dirty) way to retrofit drake to an existing script-based project. It parses individual ⁠\*.R/\*.RMD⁠ files into functions so they can be added into the drake workflow.

Usage

code_to_function(path, envir = parent.frame())

Arguments

path

Character vector, path to script.

envir

Environment of the created function.

Details

Most data science workflows consist of imperative scripts. drake, on the other hand, assumes you write functions. code_to_function() allows for pre-existing workflows to incorporate drake as a workflow management tool seamlessly for cases where re-factoring is unfeasible. So drake can monitor dependencies, the targets are passed as arguments of the dependent functions.

Value

A function to be input into the drake plan

See Also

file_in(), file_out(), knitr_in(), ignore(), no_deps(), code_to_plan(), plan_to_code(), plan_to_notebook()

Examples

## Not run: 
isolate_example("contain side effects", {
if (requireNamespace("ggplot2", quietly = TRUE)) {
# The `code_to_function()` function creates a function that makes it
# available for drake to process as part of the workflow.
# The main purpose is to allow pre-existing workflows to incorporate drake
# into the workflow seamlessly for cases where re-factoring is unfeasible.
#

script1 <- tempfile()
script2 <- tempfile()
script3 <- tempfile()
script4 <- tempfile()

writeLines(c(
  "data <- mtcars",
  "data$make <- do.call('c',",
  "lapply(strsplit(rownames(data), split=\" \"), `[`, 1))",
  "saveRDS(data, \"mtcars_alt.RDS\")"
 ),
  script1
)

writeLines(c(
  "data <- readRDS(\"mtcars_alt.RDS\")",
  "mtcars_lm <- lm(mpg~cyl+disp+vs+gear+make,data=data)",
  "saveRDS(mtcars_lm, \"mtcars_lm.RDS\")"
  ),
  script2
)
writeLines(c(
  "mtcars_lm <- readRDS(\"mtcars_lm.RDS\")",
  "lm_summary <- summary(mtcars_lm)",
  "saveRDS(lm_summary, \"mtcars_lm_summary.RDS\")"
  ),
  script3
)
writeLines(c(
  "data<-readRDS(\"mtcars_alt.RDS\")",
  "gg <- ggplot2::ggplot(data)+",
  "ggplot2::geom_point(ggplot2::aes(",
  "x=disp, y=mpg, shape=as.factor(vs), color=make))",
  "ggplot2::ggsave(\"mtcars_plot.png\", gg)"
 ),
  script4
)


do_munge <- code_to_function(script1)
do_analysis <- code_to_function(script2)
do_summarize <- code_to_function(script3)
do_vis <- code_to_function(script4)

plan <- drake_plan(
  munged   = do_munge(),
  analysis = do_analysis(munged),
  summary  = do_summarize(analysis),
  plot     = do_vis(munged)
 )

plan
# drake knows  "script1" is the first script to be evaluated and ran,
# because it has no dependencies on other code and a dependency of
# `analysis`. See for yourself:

make(plan)

# See the connections that the sourced scripts create:
if (requireNamespace("visNetwork", quietly = TRUE)) {
  vis_drake_graph(plan)
}
}
})

## End(Not run)