Many common transforms can be applied to the data with R.

The function head is very useful for working with lists, tables, data frames and even functions.

Each variable forms a column in tidy data.

Join is faster in plyr package.

mutate is used for adding new variables.

Both head and tail function do not work on strings.

Common variables are not used to apply transforms.

Use acast or dcast depending on whether you want vector/matrix/array output or data frame output.

In probability and statistics, the quantile function specifies, for a given probability in the probability distribution of a random variable, the value at which the probability of the random variable will be less than or equal to that probability.

In R, missing values are represented by the symbol NA.