data.table
based implementation.
# S3 method for relop_rename_columns ex_data_table_step( optree, ..., tables = list(), source_usage = NULL, source_limit = NULL, env = parent.frame() )
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. |
dL <- build_frame( "x", "y" | 2L , "b" | 1L , "a" | 3L , "c" ) rquery_pipeline <- local_td(dL) %.>% rename_columns(., c("x" = "y", "y" = "x")) dL %.>% rquery_pipeline#> y x #> 1 2 b #> 2 1 a #> 3 3 c