data.table based implementation.

# S3 method for relop_select_columns
ex_data_table_step(
  optree,
  ...,
  tables = list(),
  source_usage = NULL,
  source_limit = NULL,
  env = parent.frame()
)

Arguments

optree

relop operations tree.

...

not used, force later arguments to bind by name.

tables

named list map from table names used in nodes to data.tables and data.frames.

source_usage

list mapping source table names to vectors of columns used.

source_limit

if not null limit all table sources to no more than this many rows (used for debugging).

env

environment to work in.

Examples

dL <- data.frame(x = 1, y = 2, z = 3) rquery_pipeline <- local_td(dL) %.>% select_columns(., "y") dL %.>% rquery_pipeline
#> y #> 1 2