data.table based implementation.
data.table
# S3 method for relop_select_columns ex_data_table_step( optree, ..., tables = list(), source_usage = NULL, source_limit = NULL, env = parent.frame() )
relop operations tree.
not used, force later arguments to bind by name.
named list map from table names used in nodes to data.tables and data.frames.
list mapping source table names to vectors of columns used.
if not null limit all table sources to no more than this many rows (used for debugging).
environment to work in.
# NOT RUN { dL <- data.frame(x = 1, y = 2, z = 3) rquery_pipeline <- local_td(dL) %.>% select_columns(., "y") dL %.>% rquery_pipeline # }
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