add add_header_left
diff --git a/docs/awesome_table_in_pdf.Rmd b/docs/awesome_table_in_pdf.Rmd
index aaded10..c20f16f 100644
--- a/docs/awesome_table_in_pdf.Rmd
+++ b/docs/awesome_table_in_pdf.Rmd
@@ -251,3 +251,14 @@
column_spec(7, bold = T) %>%
row_spec(5, bold = T)
```
+
+# Add header column to the left
+An alternative way of grouping rows is being added to `kableExtra` 0.3.0. Unlike `group_rows`, the new function `add_header_left` adopts a similar syntax with `add_header_above`. It allows users to add multiple layers of row groups, which is a limitation of `group_rows`. A limitation of `add_header_left` is that, you can only use it in `booktabs` tables. There is no future plan to extend support to LaTeX table without booktabs because when a new layer of heading columns being added, every `cline` in normal table needs to be changed. Other limitations include incompatible with `group_rows` and a little in-stable `striped` row coloring behavior. If you don't have special need for multiple layers of heading columns or special love to this format, I will recommend you stick with `group_rows`.
+
+```{r}
+mtcars[1:10, 1:6] %>%
+ kable("latex", booktabs= T) %>%
+ add_header_above(c(" ", "Data 1" = 3, "Data 2" = 3)) %>%
+ add_header_left(c("Group A" = 3, "Group B" = 7), "Group") %>%
+ add_header_left(c("Team X" = 4, "Team Y" = 2, "Team Z" = 4), "Team")
+```