Introduce pull for extracting vectors from data frames

exercises/extracting-vectors-from-data-frames-R.md

@@ -9,4 +9,4 @@ Using the Portal data `surveys` table ([download a copy](https://ndownloader.fig
 
 1. Use `$` to extract the `weight` column into a vector
 2. Use `[]` to extract the `month` column into a vector
-3. Extract the `hindfoot_length` column into a vector and calculate the mean hindfoot length ignoring null values.
+3. Extract the `hindfoot_length` column into a vector using `pull()` and use this vector to calculate the mean hindfoot length ignoring null values

materials/converting-dataframes-vectors.md

@@ -62,6 +62,20 @@ species["species_id"]
 species[["species_id"]]
 ```
 
+* Finally, `dplyr` has a function called `pull()`
+
+```r
+pull(species, species_id)
+```
+
+* This is typically used at the end a dplyr pipeline
+
+```r
+species |>
+  filter(taxa == "Rodent") |>
+  pull(species_id)
+```
+
 ### Combining vectors to make a data frame
 
 * We can also combine vectors to make a data frame