update data

SD/20240326_1_codestyle/index.qmd

@@ -36,7 +36,6 @@ library(tidyverse)
 library(nycflights13)
 ```
 
-
 ## tidy data
 
 ```{r}
@@ -136,14 +135,20 @@ flights|>filter(dest=="IAH")|>
   group_by(year,month,day)|>summarize(n=n(),
 delay=mean(arr_delay,na.rm=TRUE))|>filter(n>10)
 
-flights|>filter(carrier=="UA",
-  dest%in%c("IAH","HOU"),sched_dep_time>
-0900,sched_arr_time<2000)|>group_by(flight)|>
-  summarize(delay=mean(
-arr_delay,na.rm=TRUE),cancelled=sum(is.na(arr_delay)),
-    n=n())|>filter(n>10)
 ```
 
+## 练习
+
+```{r}
+#| eval: false
+flights |>
+  filter(dest == "IAH") |>
+  group_by(year, month, day) |>
+  summarize(n = n(),
+    delay = mean(arr_delay, na.rm = TRUE)) |>
+  filter(n > 10)
+
+```
 
 ## quarto