From 707b332c3c499f966bb0515a3ab90711b7104147 Mon Sep 17 00:00:00 2001
From: Hadley Wickham <h.wickham@gmail.com>
Date: Mon, 23 Jan 2023 08:14:07 -0600
Subject: [PATCH] Fix case_when() logic error

Fixes #1227
---
 logicals.qmd | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/logicals.qmd b/logicals.qmd
index 6ca5cf6..7ec3c76 100644
--- a/logicals.qmd
+++ b/logicals.qmd
@@ -488,6 +488,7 @@ It takes pairs that look like `condition ~ output`.
 This means we could recreate our previous nested `if_else()` as follows:
 
 ```{r}
+x <- c(-3:3, NA)
 case_when(
   x == 0   ~ "0",
   x < 0    ~ "-ve", 
@@ -538,13 +539,15 @@ flights |>
       arr_delay < -30       ~ "very early",
       arr_delay < -15       ~ "early",
       abs(arr_delay) <= 15  ~ "on time",
-      arr_delay > 15        ~ "late",
-      arr_delay > 60        ~ "very late",
+      arr_delay < 60        ~ "late",
+      arr_delay < Inf       ~ "very late",
     ),
     .keep = "used"
   )
 ```
 
+Be wary when writing this sort of complex `case_when()` statement; my first two attempts used a mix of `<` and `>` and I kept accidentally creating overlapping conditions.
+
 ### Compatible types
 
 Note that both `if_else()` and `case_when()` require **compatible** types in the output.