Update vignettes/datatable-reference-semantics.Rmd

Co-authored-by: Benjamin Schwendinger <[email protected]>

Author: venom1204

vignettes/datatable-reference-semantics.Rmd

@@ -371,21 +371,18 @@ A short example:
 ```{r}
 DT = data.table(a = 1:3)
 
-# Create three variables using the different methods
-x_ref = DT$a        # 1. By reference with $
-y_cpy = DT[, a]     # 2. By copy with []
-z_cpy = copy(DT$a)  # 3. Forced copy with copy()
+# three ways to get the column
+x_ref = DT$a        # may be a reference
+y_cpy = DT[, a]     # always a copy
+z_cpy = copy(DT$a)  # forced copy
 
-# Now, modify the original data.table by reference
+# modify DT by reference
 DT[, a := a + 10L]
 
-# Check the variables:
-x_ref 
-#> [1] 11 12 13
-y_cpy
-#> [1] 1 2 3
-z_cpy 
-#> [1] 1 2 3
+# observe results
+x_ref   # may show 11 12 13
+y_cpy   # 1 2 3
+z_cpy   # 1 2 3
 ```
 
 To select a single column as a vector, remember: