ex_data_table_step.relop_natural_join: Natural join.

In WinVector/rqdatatable: 'rquery' for 'data.table'

Natural join.

Description

data.table based implementation.

Usage

## S3 method for class 'relop_natural_join'
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

d1 <- build_frame(
    "key", "val", "val1" |
      "a"  , 1  ,  10    |
      "b"  , 2  ,  11    |
      "c"  , 3  ,  12    )
d2 <- build_frame(
    "key", "val", "val2" |
      "a"  , 5  ,  13    |
      "b"  , 6  ,  14    |
      "d"  , 7  ,  15    )

# key matching join
optree <- natural_join(local_td(d1), local_td(d2),
                       jointype = "FULL", by = 'key')
ex_data_table(optree)

# full cross-product join
# (usually with jointype = "FULL", but "LEFT" is more
# compatible with rquery field merge semantics).
optree2 <- natural_join(local_td(d1), local_td(d2),
                        jointype = "LEFT", by = NULL)
ex_data_table(optree2)
# notice ALL non-"by" fields take coalese to left table.

WinVector/rqdatatable documentation built on Aug. 22, 2023, 3:25 p.m.