select_instances: Select instances of a flat table by value

In rolap: Obtaining Star Databases from Flat Tables

Select instances of a flat table by value

Description

Select only the indicated instances from the flat table.

Usage

select_instances(ft, not, attributes, values)

## S3 method for class 'flat_table'
select_instances(ft, not = FALSE, attributes = NULL, values)

Arguments

ft	A flat_table object.
not	A boolean.
attributes	A vector of names.
values	A list of value vectors.

Details

Several values can be indicated for attributes (performs an OR operation) or several attributes and a value for each one (performs an AND operation).

If the parameter not is true, the reported values are those that are not included.

Value

A flat_table object.

See Also

flat_table

Other flat table transformation functions: add_custom_column(), remove_instances_without_measures(), replace_empty_values(), replace_string(), replace_unknown_values(), select_attributes(), select_instances_by_comparison(), select_measures(), separate_measures(), transform_attribute_format(), transform_from_values(), transform_to_attribute(), transform_to_measure(), transform_to_values()

Examples

ft <- flat_table('iris', iris) |>
  select_instances(attributes = c('Species'),
                   values = c('versicolor', 'virginica'))

ft <- flat_table('ft_num', ft_num) |>
  select_instances(
    not = TRUE,
    attributes = c('Year', 'WEEK'),
    values = list(c('1962', '2'), c('1964', '2'))
  )

rolap documentation built on June 8, 2025, 10:23 a.m.