Remove mention of 'rownames()' from lesson key points

episodes/05-data-structures-part2.Rmd

@@ -390,7 +390,7 @@ The object `gapminder` is a data frame with columns
 - Use `cbind()` to add a new column to a data frame.
 - Use `rbind()` to add a new row to a data frame.
 - Remove rows from a data frame.
-- Use `str()`, `summary()`, `nrow()`, `ncol()`, `dim()`, `colnames()`, `rownames()`, `head()`, and `typeof()` to understand the structure of a data frame.
+- Use `str()`, `summary()`, `nrow()`, `ncol()`, `dim()`, `colnames()`, `head()`, and `typeof()` to understand the structure of a data frame.
 - Read in a csv file using `read.csv()`.
 - Understand what `length()` of a data frame represents.