fixes 292

episodes/03-basics-factors-dataframes.Rmd

@@ -216,14 +216,15 @@ these columns, as well as mean, median, and interquartile ranges. Many of the
 other variables (e.g. `sample_id`) are treated as characters data (more on this
 in a bit).
 
-There is a lot to work with, so we will subset the first three columns into a
-new data frame using the `data.frame()` function. To subset/index a two dimensional
-variable, we need to define them on the appropriate side of the brackets. The left
-hand side of the comma indicates the rows you want to subset, and the right is the
-column position (e.g. ["row index", "column index"]).
+There is a lot to work with, so we will subset the columns into a new data frame using
+the `data.frame()` function. To subset/index a two dimensional variable, we need to
+define them on the appropriate side of the brackets. The left hand side of the comma
+indicates the rows you want to subset, and the right is the column position 
+(e.g. ["row index", "column index"]).
+
+Let's put the columns 1, 2, 3, and 6 into a new data frame called subset:
 
 ```{r, purl=FALSE}
-## put the first three columns of variants into a new data frame called subset
 ## Notice that we are wrapping the numbers in a c() function, to indicate a vector
 ## in the right hand side of the comma. 
 subset <- data.frame(variants[, c(1:3, 6)])