Manual

All functions

IDate() as.IDate() ITime() as.ITime() IDateTime() as.character.ITime() as.Date.IDate() as.IDate.Date() as.IDate.default() as.ITime.character() as.ITime.default() as.ITime.POSIXlt() as.ITime.times() as.list.IDate() as.POSIXct.IDate() as.POSIXct.ITime() as.POSIXlt.ITime() c.IDate() c.ITime() format.ITime() IDateTime.default() mean.IDate() mean.ITime() print.ITime() rep.IDate() rep.ITime() round.IDate() round.ITime() trunc.ITime() seq.IDate() seq.ITime() second() minute() hour() yday() wday() mday() week() isoweek() isoyear() month() quarter() year() yearmon() yearqtr() IDate-class ITime-class

Integer based date class

J() CJ() SJ()

Creates a join data.table

address()

Address in RAM of a variable

all.equal() all.equal.data.table()

Equality Test Between Two Data Tables

as.data.table() as.data.table.array() as.data.table.matrix() as.data.table.list() as.data.table.data.frame() as.data.table.data.table() as.data.table.factor() as.data.table.ordered() as.data.table.integer() as.data.table.numeric() as.data.table.logical() as.data.table.character() as.data.table.Date() is.data.table()

Coerce to data.table

as.data.table.xts()

Efficient xts to as.data.table conversion

as.matrix() as.matrix.data.table()

Convert a data.table to a matrix

as.xts.data.table()

Efficient data.table to xts conversion

:= set() let()

Assignment by reference

between() %between% inrange() %inrange%

Convenience functions for range subsets

binary_reopener() binary_reopener.default() binary_reopener.file() binary_reopener.gzfile() binary_reopener.bzfile() binary_reopener.url() binary_reopener.unz() binary_reopener.pipe()

Create a function to open connections in binary mode

cbindlist() setcbindlist() cbind() cbind.data.table()

Column bind multiple data.tables

cdatatable()

data.table exported C routines

chmatch() %chin% chorder() chgroup()

Faster match of character vectors

fcoalesce() setcoalesce()

Coalescing missing values

copy()

Copy an entire object

data.table-package data.table() Ops.data.table() is.na.data.table() [.data.table . .( .() ..

Enhanced data.frame

class:data.table data.table-class

S4 Definition for data.table

data.table-condition-classes

Condition Handling with Classed Conditions

data.table-options data.table.options() datatable.options() datatable-options

Global Options for the data.table Package

datatable-optimize datatable.optimize() data.table-optimize data.table.optimize() gforce() GForce() autoindex() autoindexing() auto-index auto-indexing rounding()

Optimisations in data.table

dcast.data.table() dcast()

Fast dcast for data.table

duplicated() duplicated.data.table() unique() unique.data.table() anyDuplicated() anyDuplicated.data.table() uniqueN()

Determine Duplicate Rows

fcase()

fcase

fctr() factor()

Create a factor retaining original ordering

fdroplevels() droplevels() droplevels.data.table() setdroplevels()

Fast droplevels

fifelse() ifelse()

Fast ifelse

foverlaps()

Fast overlap joins

frank() frankv() rank()

Fast rank

fread()

Fast and friendly file finagler

frev() rev()

Fast reverse

rolling() sliding() moving() running() froll() frollmean() frollsum() frollmax() frollmin() frollprod() frollmedian() frollvar() frollsd() roll() rollmean() rollsum() rollmax() rollmin() rollprod() rollmedian() rollvar() rollsd()

Rolling functions

frolladapt()

Adapt rolling window to irregularly spaced time series

frollapply() rollapply()

Rolling user-defined function

fsort()

Fast parallel sort

fwrite()

Fast CSV writer

rollup() cube() groupingsets() rollup.data.table() cube.data.table() groupingsets.data.table()

Grouping Set aggregation for data tables

first() last()

First/last item of an object

.Last.updated Last.updated()

Number of rows affected by last update

like() %like% %ilike% %flike% %plike%

Convenience function for calling grep

measure() measurev()

Specify measure.vars via regex or separator

melt.data.table() melt()

Fast melt for data.table

merge() merge.data.table()

Merge two data.tables

mergelist() setmergelist()

Merge multiple data.tables

na.omit.data.table() na.omit()

Remove rows with missing values on columns specified

nafill() fill() setnafill() locf() nocb() na.fill()

Fill missing values

%notin%

Convenience operator for checking if an example is not in a set of elements

setDTthreads() getDTthreads() openMP() openmp()

Set or get number of threads that data.table should use

patterns()

Obtain matching indices corresponding to patterns

print.data.table() format_col() format_col.default() format_col.POSIXct() format_col.expression() format_list_item() format_list_item.default()

data.table Printing Options

rbindlist() rbind.data.table() rbind()

Makes one data.table from a list of many

rleid() rleidv()

Generate run-length type group id

rowid() rowidv()

Generate unique row ids within each group

rowwiseDT()

Create a data.table row-wise

.selfref.ok

Tests self reference of a data.table

setDF()

Coerce a data.table to data.frame by reference

setDT()

Coerce lists and data.frames to data.table by reference

setNumericRounding() getNumericRounding()

Change or turn off numeric rounding

setattr() setnames()

Set attributes of objects by reference

setcolorder()

Fast column reordering of a data.table by reference

setkey() setkeyv() key() haskey() setindex() setindexv() indices()

Create key on a data.table

setops() intersect() fintersect() setdiff() fsetdiff() except() fexcept() union() funion() setequal() fsetequal()

Set operations for data tables

setorder() setorderv() order() fastorder() forder() forderv() sort_by()

Fast row reordering of a data.table by reference

shift() lead() lag()

Fast lead/lag for vectors and lists

shouldPrint()

For use by packages that mimic/divert auto printing e.g. IRkernel and knitr

special-symbols datatable-symbols .SD .I .GRP .BY .N .EACHI .NGRP .NATURAL .ROW

Special symbols

split() split.data.table()

Split data.table into chunks in a list

subset() subset.data.table()

Subsetting data.tables

substitute2() substitute() I()

Substitute expression

tables()

Display 'data.table' metadata

test()

Test assertions for equality, exceptions and console output

test.data.table()

Runs a set of tests

timetaken()

Pretty print of time taken

transform() transform.data.table() within() within.data.table()

Data table utilities

transpose()

Efficient transpose of list

truelength() setalloccol() alloc.col() setallocrow()

Over-allocation access

tstrsplit() strsplit()

strsplit and transpose the resulting list efficiently

update_dev_pkg()

Perform update of development version of a package