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()

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.

cdt

data.table exported C routines

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

Faster match of character vectors

fcoalesce()

Coalescing missing values

copy()

Copy an entire object

data.table-class

S4 Definition for data.table

data.table() `[`(<data.table>)

Enhanced data.frame

datatable.optimize

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

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%`

Convenience function for calling grep.

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

setDTthreads() getDTthreads()

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

patterns()

Obtain matching indices corresponding to patterns

print(<data.table>)

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

Special symbols

split(<data.table>)

Split data.table into chunks in a list

subset(<data.table>)

Subsetting data.tables

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