doBy (version 4.6.21)

by-subset: Finds subsets of a dataframe which is split by variables in a formula.

Description

A data frame is split by a formula into groups. Then subsets are found within each group, and the result is collected into a data frame.

Usage

subset_by(data, formula, subset, select, drop = FALSE, join = TRUE, ...)
subsetBy(
  formula,
  subset,
  data = parent.frame(),
  select,
  drop = FALSE,
  join = TRUE,
  ...
)

Value

A data frame.

Arguments

data

A data frame.

formula

A right hand sided formula or a character vector of variables to split by.

subset

logical expression indicating elements or rows to keep: missing values are taken as false.

select

expression, indicating columns to select from a data frame.

drop

passed on to [ indexing operator.

join

If FALSE the result is a list of data frames (as defined by 'formula'); if TRUE one data frame is returned.

...

further arguments to be passed to or from other methods.

Author

Søren Højsgaard,

See Also

splitBy, split_by

Examples

data(dietox)
subsetBy(~Evit, Weight < mean(Weight), data=dietox)