sub-sub-.big.data.table: Extract from big.data.table
In jangorecki/big.data.table: Parallel distributed computing for data.table

Extract from big.data.table

## S3 method for class 'big.data.table'
x[[j, expr, lazy = TRUE, send = FALSE, i, ...,
  simplify = TRUE, rbind = TRUE, parallel = TRUE,
  outer.aggregate = getOption("bigdatatable.outer.aggregate", FALSE),
  .log = getOption("bigdatatable.log", FALSE)]]

`x`	big.data.table object.
`j`	numeric scalar, if provided then all other arguments are ignored and subset behaves the same way as for data.table, but returns 0 length column.
`expr`	expression to be evaluated on node where data.table objects are stored as 'x' variable in '.GlobalEnv'.
`lazy`	logical if TRUE then expr is substituted.
`send`	logical, if TRUE submit expression appended with 'TRUE' to not fetch potentially big results from provided expr, useful for data.table __set*__ or ':=' functions.
`i`	numeric restrict expression to particular nodes
`simplify`	logical passed to 'bdt.eval', affects the type of returned object.
`rbind`	logical passed to 'bdt.eval', affects the type of returned object.
`parallel`	logical if parallel TRUE (default) it will send expression to nodes using 'wait=FALSE' and collect results afterward executing each node in parallel.
`outer.aggregate`	logical or a function, if TRUE will able the same query to rbind of results from each node, should not be used with '.SD', '.N', etc. Also conflicts with filtering in 'i'. Can be also a function taking first argument 'x' rbinded data.table.
`.log`	logical if TRUE then logging will be done using logR to postgres db.
`...`	ignored.

When using *j* arg the 0 length variable from underlying data is returned. Otherwise the results from expression evaluated as *lapply*. When using *rbind* or *simplify* the returned list be can simplified.

jangorecki/big.data.table documentation built on May 18, 2019, 12:24 p.m.