Implement drop columns.

Source: R/relop_select_columns.R

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