Select block constructor — new_select

This block allows performing column subsetting on data.frame objects (see dplyr::select()). Columns can be selected and reordered by dragging, and an exclude mode allows for negative selection using dplyr's minus syntax. Optionally, distinct rows can be kept after selection.

Usage

new_select_block(columns = character(), exclude = FALSE, distinct = FALSE, ...)

Arguments

columns: Selected columns (character vector). If empty, selects all columns.
exclude: Logical. If TRUE, uses exclude mode (dplyr minus syntax: -c(col1, col2)). If FALSE (default), uses include mode (selects specified columns).
distinct: Logical. If TRUE, keeps only distinct/unique rows after selecting columns. If FALSE (default), returns all rows. This replaces the old new_distinct_block() functionality.
...: Forwarded to blockr.core::new_transform_block()

Value

A transform block object of class select_block.

Details

Note: This block replaces the deprecated new_distinct_block(). Use the distinct parameter to get unique rows after column selection.

The select block provides a sortable multi-select interface where columns can be:

Selected/deselected by clicking
Reordered by dragging (order is preserved in output)
Removed individually using the × button

Include mode (exclude = FALSE, default):

Selected columns are included in output
Empty selection = select all (select(data, dplyr::everything()))

Exclude mode (exclude = TRUE):

Selected columns are excluded from output using minus syntax
Empty selection = select all (select(data))
Efficient for large datasets when you want to remove just a few columns

Distinct mode (distinct = TRUE):

Keeps only distinct rows after column selection
Equivalent to piping select() output to distinct()
Useful for finding unique combinations of selected columns

Examples

# Create a select block
new_select_block(columns = c("mpg", "cyl", "hp"))
#> <select_block<transform_block<block>>>
#> Name: "Select"
#> Data inputs: "data"
#> Initial block state:
#>  $ columns : chr [1:3] "mpg" "cyl" "hp"
#>  $ exclude : logi FALSE
#>  $ distinct: logi FALSE
#> Constructor: blockr.dplyr::new_select_block()

if (interactive()) {
  # Basic usage with mtcars dataset
  library(blockr.core)
  serve(new_select_block(), list(data = mtcars))

  # With initial column selection
  serve(new_select_block(columns = c("mpg", "cyl", "hp")), list(data = mtcars))

  # Exclude mode (select all except specified columns)
  serve(new_select_block(columns = c("gear", "carb"), exclude = TRUE), list(data = mtcars))

  # Select with distinct (unique combinations)
  serve(new_select_block(columns = c("cyl", "gear"), distinct = TRUE), list(data = mtcars))

  # Full deduplication (distinct on all columns)
  serve(new_select_block(distinct = TRUE), list(data = mtcars))

  # Connected blocks example
  serve(
    new_board(
      blocks = list(
        a = new_dataset_block(),
        b = new_select_block()
      ),
      links = links(
        from = c("a"),
        to = c("b")
      )
    )
  )
}