Returns the last n elements of a vector, matrix, or data frame.

Returns the first n elements of a vector, matrix, or data frame.

Returns the number of elements in a vector or the number of components in an object.

Subsets a data frame or vector based on specified conditions.

Merges two data frames based on common columns or row names.

Generates summary statistics of the input data.

Computes sample quantiles of a numeric vector.

Calculates the maximum value in a numeric vector.

Calculates the minimum value in a numeric vector.

Calculates the sample variance of a numeric vector.

Calculates the standard deviation of a numeric vector.

Calculates the sum of numeric values in a vector.

Calculates the median of a numeric vector.

Calculates the arithmetic mean of a numeric vector.