update leture 2

SD/1.1_R语言介绍/_demo.qmd

@@ -86,6 +86,53 @@ substr("Monday", 1, 3)
 ```
 
 
+# tidy
+
+
+```{r}
+require(readxl)
+
+aqdf <-readxl::read_xlsx("../../data/airquality.xlsx", sheet = "metadf")
+
+# install.packages("skimr")
+
+aqdf |>
+  skimr::skim()
+
+# base
+
+# tidyverse
+
+aqdf |>
+  dplyr::group_by(Area) |>
+  dplyr::summarize(
+    n = n(),
+    lon.mean = mean(lon, na.rm = TRUE),
+    lon.sd = sd(lat, na.rm = TRUE)
+  ) |>
+  dplyr::filter(Area %in% c("北京市", "天津市", "上海市", "重庆市")) |>
+  ggplot(aes(x = n, y = lon.mean)) +
+  geom_point() +
+  geom_line() +
+  geom_errorbar(
+    aes(ymin = lon.mean - lon.sd,
+      ymax = lon.mean + lon.sd)
+  )
+
+
+
+
+
+
+
+readxl::read_xlsx("./airquality.xlsx")
+
+flights|>
+  filter(dest=="IAH")|>
+  group_by(year,month,day)|>summarize(n=n(),
+delay=mean(arr_delay,na.rm=TRUE))|>filter(n>10)
+
+```