Function reference • data.table

All functions

as.IDate() as.Date(<IDate>) as.POSIXct(<IDate>) round(<IDate>) as.ITime() round(<ITime>) trunc(<ITime>) as.POSIXct(<ITime>) as.character(<ITime>) format(<ITime>) IDateTime() second() minute() hour() yday() wday() mday() week() isoweek() month() quarter() year() yearmon() yearqtr(): Integer based date class

SJ() CJ(): Creates a join data.table

address(): Address in RAM of a variable

all.equal(<data.table>): Equality Test Between Two Data Tables

as.data.table() is.data.table(): Coerce to data.table

as.data.table(<xts>): Efficient xts to as.data.table conversion

as.matrix(<data.table>): Convert a data.table to a matrix

as.xts.data.table(): Efficient data.table to xts conversion

set(): Assignment by reference

between() `%between%` inrange() `%inrange%`: Convenience functions for range subsets.

cdatatable: data.table exported C routines

chmatch() `%chin%` chorder() chgroup(): Faster match of character vectors

fcoalesce(): Coalescing missing values

copy(): Copy an entire object

class:data.table data.table-class: S4 Definition for data.table

data.table() `[`(<data.table>): Enhanced data.frame

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>): Fast dcast for data.table

duplicated(<data.table>) unique(<data.table>) anyDuplicated(<data.table>) uniqueN(): Determine Duplicate Rows

fcase(): fcase

fdroplevels() droplevels(<data.table>): Fast droplevels

fifelse(): Fast ifelse

foverlaps(): Fast overlap joins

frank() frankv(): Fast rank

fread(): Fast and friendly file finagler

frollmean() frollsum() frollapply(): Rolling functions

fsort(): Fast parallel sort

fwrite(): Fast CSV writer

rollup() cube() groupingsets(): Grouping Set aggregation for data tables

first() last(): First/last item of an object

.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>): Fast melt for data.table

merge(<data.table>): Merge two data.tables

na.omit(<data.table>): Remove rows with missing values on columns specified

nafill() setnafill(): Fill missing values

`%notin%`: Convenience operator for checking if an example is not in a set of elements

setDTthreads() getDTthreads(): Set or get number of threads that data.table should use

patterns(): Obtain matching indices corresponding to patterns

print(<data.table>) format_col() format_list_item(): data.table Printing Options

rbindlist(): 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

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() setindex() setindexv() key() indices() haskey(): Create key on a data.table

fintersect() fsetdiff() funion() fsetequal(): Set operations for data tables

setorder() setorderv(): Fast row reordering of a data.table by reference

shift(): 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: Special symbols

split(<data.table>): Split data.table into chunks in a list

subset(<data.table>): Subsetting data.tables

substitute2(): 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

transpose(): Efficient transpose of list

truelength() setalloccol() alloc.col(): Over-allocation access

tstrsplit(): strsplit and transpose the resulting list efficiently

update_dev_pkg(): Perform update of development version of a package