LazyIndex-class: The 'LazyIndex' class and methods.

In DelayedDataFrame: Delayed operation on DataFrame using standard DataFrame metaphor

Description

The LazyIndex class is designed to carry mapping indexes for DelayedDataFrame columns. So that some operations (e.g., subsetting) on DelayedDataFrame are delayed until a realization call is incurred. (e.g., as.list(), DataFrame(), ...)

LazyIndex constructor.

the subsetting method for LazyIndex object.

Usage

LazyIndex(listData = list(), index = integer())

## S4 method for signature 'LazyIndex'
cbind(..., deparse.level = 1)

## S4 method for signature 'LazyIndex,ANY,ANY,ANY'
x[i, j, ..., drop = TRUE]

Arguments

listData	the list data for all mapping indexes that are used in corresponding DelayedDataFrame object.
index	the position of mapping indexes in listData for each column of the corresponding DelayedDataFrame object.
...	LazyIndex objects.
deparse.level	See ?base::cbind for a description of this argument.
x	LazyIndex object.
i	row subscript for LazyIndex, which will subset the listData slot.
j	column subscript for LazyIndex, which will subset the index slot.
drop	Logical. Wheter to drop the dimension if any of the dimensions has length 1. Default is TRUE.

Details

the cbind,LazyIndex method is defined to bind the LazyIndexes column-wise when cbind,DelayedDataFrame function is called.

Value

a LazyIndex object.

DelayedDataFrame documentation built on Nov. 8, 2020, 5:28 p.m.