Merge pull request #2 from rstats-wtf/update-examples

revise workshop examples

01_exercise/01_debugging_comfy.R

@@ -0,0 +1,58 @@
+# Origin -----------------------------------------------------------------------
+# This example was originally used inJenny Bryan's rstudio::conf(2020) keynote
+# Object of type 'closure' is not subsettable,
+# https://github.com/jennybc/debugging
+
+
+# open 01_sourceme to inspect & review code ---------------------------------------
+# try file.edit()
+
+
+# source functions -------------------------------------------------------------
+# source in 01_exercise/01_sourceme.R 
+
+# view fruit data --------------------------------------------------------------
+
+# successful execution ---------------------------------------------------------
+# confirm function works for berry
+fruit_avg(fruit, "berry")
+
+# error on execution -----------------------------------------------------------
+# observe error
+fruit_avg(fruit, "peach")
+
+# identify location of error ---------------------------------------------------
+# try traceback()
+
+# copy and paste traceback results as a comment here to compare with next exercise
+
+
+# modify options for a richer traceback via rlang ------------------------------
+
+# copy and paste traceback results as a comment here to compare with next exercise
+
+
+# interactive debugging --------------------------------------------------------
+# enter interactive debugger by inserting browser() into the fruit_avg() function
+# trigger interactive debugger by executing function
+
+# use these commands at the Browse[]> prompt to navigate the debugger
+
+# | command | operation               |
+# |---------|-------------------------|
+# | `n`     | next statement          |
+# | `c`     | continue                |
+# | `s`     | step into function call |
+# | `f`     | finish loop / function  |
+# | `where` | show previous calls     |
+# | `Q`     | quit debugger           |
+
+# while in the debugger, explore the objects in your environment
+# with ls.str()
+
+# Can you determine exactly why the bug is occurring?
+# If you have time, try to fix it!
+
+
+
+

01_exercise/01_debugging_solution.R

@@ -0,0 +1,70 @@
+# Origin -----------------------------------------------------------------------
+# This example was originally used inJenny Bryan's rstudio::conf(2020) keynote
+# Object of type 'closure' is not subsettable,
+# https://github.com/jennybc/debugging
+
+
+# open sourceme to inspect & review code ---------------------------------------
+file.edit("01_exercise/01_sourceme.R")
+
+
+# source functions -------------------------------------------------------------
+# open 01_exercise/01_sourceme.R and click on Source button
+# OR
+source("01_exercise/01_sourceme.R")
+
+
+# view fruit data --------------------------------------------------------------
+fruit
+
+
+# successful execution ---------------------------------------------------------
+# confirm function works for berry
+fruit_avg(fruit, "berry")
+
+# error on execution -----------------------------------------------------------
+# observe error
+fruit_avg(fruit, "peach")
+
+# identify location of error ---------------------------------------------------
+traceback()
+
+# copy and paste traceback results as a comment here to compare with next exercise
+
+
+# modify options for a richer traceback ----------------------------------------
+options(error = rlang::entrace) 
+fruit_avg(fruit, "peach")
+rlang::last_error()
+rlang::last_trace()
+
+# copy and paste traceback results as a comment here to compare with next exercise
+
+
+# interactive debugging --------------------------------------------------------
+# enter interactive debugger by inserting `browser()` statement in  
+# the fruit_avg() function in 01_sourceme.R
+# Restart R, re-source file
+source("01_exercise/01_sourceme.R")
+
+# trigger interactive debugger
+fruit_avg(fruit, "peach")
+
+# use these commands at the Browse[]> prompt to navigate the debugger
+
+# | command | operation               |
+# |---------|-------------------------|
+# | `n`     | next statement          |
+# | `c`     | continue                |
+# | `s`     | step into function call |
+# | `f`     | finish loop / function  |
+# | `where` | show previous calls     |
+# | `Q`     | quit debugger           |
+
+# while in the debugger, explore the objects in your environment
+# with ls.str()
+
+# Can you determine exactly why the bug is occurring?
+# If you have time, try to fix it!
+
+

01_exercise/01_debugging_spartan.R

@@ -0,0 +1,43 @@
+# Origin -----------------------------------------------------------------------
+# This example was originally used inJenny Bryan's rstudio::conf(2020) keynote
+# Object of type 'closure' is not subsettable,
+# https://github.com/jennybc/debugging
+
+
+# open 01_sourceme to inspect & review code ---------------------------------------
+
+
+# source functions -------------------------------------------------------------
+
+
+# view fruit data --------------------------------------------------------------
+
+
+# successful execution ---------------------------------------------------------
+# confirm function works for berry
+fruit_avg(fruit, "berry")
+
+# error on execution -----------------------------------------------------------
+# observe error
+fruit_avg(fruit, "peach")
+
+
+
+# identify location of error ---------------------------------------------------
+
+# copy and paste traceback results as a comment here to compare with next exercise
+
+
+
+# modify options for a richer traceback ----------------------------------------
+
+
+# copy and paste traceback results as a comment here to compare with next exercise
+
+
+# interactive debugging --------------------------------------------------------
+# enter interactive debugger
+
+# Can you determine exactly why the bug is occurring?
+# If you have time, try to fix it!
+

01_exercise/01_sourceme.R

@@ -0,0 +1,14 @@
+fruit <- data.frame(
+  row.names = c("calories", "weight", "yumminess"),
+  blackberry = c(4L, 9L, 6L),
+  blueberry = c(1L, 2L, 8L),
+  peach = c(59L, 150L, 10L),
+  plum = c(30L, 78L, 5L)
+)
+
+fruit_avg <- function(dat, pattern) {
+  cols <- grep(pattern, names(dat))
+  mini_dat <- dat[ , cols]
+  message("Found ", ncol(mini_dat), " fruits!")
+  rowMeans(mini_dat)
+}