ryan-heslin · January 3, 2022 23:56 · Jan 3, 2022
diff --git a/search_error.md b/search_error.md
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+Friendly error messages are unfortunately not one of R's strengths. Often, running buggy code will yield something like:
+
+```r
+DF <- subset(mtcars, cyl > 4)
+df$mpg <- round(df$mpg)
+
+#> Error in df$mpg : object of type 'closure' is not subsettable
+```
+Huh? A closure is an R function with an enclosing environment (that is, one that can access the environment where it was defined).
+`df` is one such function, which gives the F distribution. In plain English, the error message is saying you can't extract an element from a function as if it were a vector.
+
+But how many R novices who run into this error for the first time can figure that out on their own? (I certainly couldn't!). Then the only
+way out is to Google the error message and find an explanation. But copying the code into a web browser breaks focus and wastes time. We can
+automate that task.
+
+First, define a function to Google a query from within R, which is suprisingly simple:
+
+```r
+google <- function(query) {
+    browseURL(paste0("http://www.google.com/search?q=", query))
+}
+```
+
+We just have to create a query URL and send it to `browseURL`. Extracting the error message is a little more involved, but not too bad:
+
+```r
+# Google most recent error message
+search_error <- function(stackoverflow = TRUE) {
+    if ((error <- capture.output(cat(geterrmessage()))[1]) == "") {
+    cat("No error messages in buffer")
+    return()
+    }
+    google(paste(error, ifelse(stackoverflow, "site:stackoverflow.com", "")))
+}
+```
+`geterrmessage` does...pretty much that. `capture.output` and `cat` get the text without the ending newline. Error messages can have
+length greater than 1 (a lot of `tidyverse` error messages are like that), so I subset only the first element to capture the most essential
+information. The rest is details: an `if` clause to abort if there are no recorded errors (if only!), and an argument letting you restrict
+the search to StackOverflow.
+
+I hope these functions relieve some of the tedium of debugging.
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