Reference card

Note

Want a quick and handy q reference resource? Download the q Cheat Sheet (PDF download).

Keywords

abs	cos	enlist	hdel	lower	msum	read0	sin	union	xcol
acos	count	eval	hopen	lsq	neg	read1	sqrt	update	xcols
aj aj0	cov	except	hsym	ltime	next	reciprocal	ss	upper	xdesc
ajf ajf0	cross	exec	iasc	ltrim	not	reval	ssr	upsert	xexp
all	csv	exit	idesc	mavg	null	reverse	string	use	xgroup
and	cut	exp	if	max	or	rload	sublist	value	xkey
any	delete	fby	ij ijf	maxs	over	rotate	sum	var	xlog
asc	deltas	fills	in	mcount	parse	rsave	sums	view	xprev
asin	desc	first	insert	md5	peach	rtrim	sv	views	xrank
asof	dev	fkeys	inter	mdev	pj	save	svar	vs
atan	differ	flip	inv	med	prd	scan	system	wavg
attr	distinct	floor	key	meta	prds	scov	tables	where
avg	div	get	keys	min	prev	sdev	tan	while
avgs	do	getenv	last	mins	prior	select	til	within
bin binr	dsave	group	like	mmax	rand	set	trim	wj wj1
ceiling	each	gtime	lj ljf	mmin	rank	setenv	type	wsum
cols	ej	hclose	load	mmu	ratios	show	uj ujf	xasc
cor	ema	hcount	log	mod	raze	signum	ungroup	xbar

By category

control	do, exit, if, while
env	getenv, gtime, ltime, setenv, use
interpret	eval, parse, reval, show, system, value
io	dsave, get, hclose, hcount, hdel, hopen, hsym, load, read0, read1, rload, rsave, save, set
iterate	each, over, peach, prior, scan
join	aj aj0, ajf ajf0, asof, ej, ij ijf, lj ljf, pj, uj ujf, wj wj1
list	count, cross, cut, enlist, except, fills, first, flip, group, in, inter, last, mcount, next, prev, raze, reverse, rotate, sublist, sv, til, union, vs, where, xprev
logic	all, and, any, not, or
math	abs, acos, asin, atan, avg, avgs, ceiling, cor, cos, cov, deltas, dev, div, ema, exp, floor, inv, log, lsq, mavg, max, maxs, mdev, med, min, mins, mmax, mmin, mmu, mod, msum, neg, prd, prds, rand, ratios, reciprocal, scov, sdev, signum, sin, sqrt, sum, sums, svar, tan, var, wavg, within, wsum, xexp, xlog
meta	attr, null, tables, type, view, views
query	delete, exec, fby, select, update
sort	asc, bin binr, desc, differ, distinct, iasc, idesc, rank, xbar, xrank
table	cols, csv, fkeys, insert, key, keys, meta, ungroup, upsert, xasc, xcol, xcols, xdesc, xgroup, xkey
text	like, lower, ltrim, md5, rtrim, ss, ssr, string, trim, upper

.Q.id (sanitize), .Q.res (reserved words)

Operators

`.`	Apply, Index, Trap, Amend	`@`	Apply At, Index At, Trap At, Amend At
`$`	Cast, Tok, Enumerate, Pad, `mmu`
`!`	Dict, Enkey, Unkey, Enumeration, Flip Splayed, Display, internal, Update, Delete, `lsq`
`?`	Find, Roll, Deal, Enum Extend, Select, Exec, Simple Exec, Vector Conditional
`+ - * %`	Add, Subtract, Multiply, Divide
`= <> ~`	Equals, Not Equals, Match
`< <= >= >`	Less Than, Up To, At Least, Greater Than
`\| &`	Greater (OR), Lesser, AND
`#`	Take, Set Attribute	`_`	Cut, Drop	`:`	Assign
`^`	Fill, Coalesce	`,`	Join	`'`	Compose
`0: 1: 2:`	File Text, File Binary, Dynamic Load
`0 ±1 ±2 ±n`	write to console, stdout, stderr, handle n
`.: @: $: !: ?: +: -: *: %: =: ~: <: >: \|: &: #: _: ^: ,:`				Assign through operator

Overloaded glyphs

Iterators

maps accumulators ' Each, each, Case /: Each Right / Over, over ': Each Parallel, peach \: Each Left \ Scan, scan ': Each Prior, prior

Execution control

.[f;x;e] Trap : Return do exit $[x;y;z] Cond @[f;x;e] Trap-At ' Signal if while :[v;p1;r1;...] Pattern conditional

Debugging

Other

` pop stack :: identity \x system cmd x . push stack generic null \ abort global amend \\ quit q set view / comment

() precedence [;] expn block {} lambda ` symbol (;) list argt list ; separator `: filepath ([]..) table

Attributes

g grouped p parted s sorted u unique

Set Attribute

Command-line options and system commands

file
`\a`	tables	`\r`	rename
`-b`	blocked	`-s` `\s`	secondary processes
`\b` `\B`	views	`-S` `\S`	random seed
`-c` `\c`	console size	`-t` `\t`	timer ticks
`-C` `\C`	HTTP size	`\ts`	time and space
`\cd`	change directory	`-T` `\T`	timeout
`\d`	directory	`-u` `-U` `\u`	usr-pwd
`-e` `\e`	error traps	`-u`	disable syscmds
`-E` `\E`	TLS server mode	`\v`	variables
`\f`	functions	`-w` `\w`	memory
`-g` `\g`	garbage collection	`-W` `\W`	week offset
`\l`	load file or directory	`\x`	expunge
`-l` `-L`	log sync	`-z` `\z`	date format
`-o` `\o`	UTC offset	`\1` `\2`	redirect
`-p` `\p`	listening port	`\_`	hide q code
`-P` `\P`	display precision	`\`	terminate
`-q`	quiet mode	`\`	toggle q/k
`-r` `\r`	replicate	`\\`	quit

system

Command-line options, System commands, OS commands

Basic datatypes n c name sz literal null inf SQL Java .Net ------------------------------------------------------------------------------------ 0 * list 1 b boolean 1 0b Boolean boolean 2 g guid 16 0Ng UUID GUID 4 x byte 1 0x00 Byte byte 5 h short 2 0h 0Nh 0Wh smallint Short int16 6 i int 4 0i 0Ni 0Wi int Integer int32 7 j long 8 0j 0Nj 0Wj bigint Long int64 0 0N 0W 8 e real 4 0e 0Ne 0We real Float single 9 f float 8 0.0 0n 0w float Double double 0f 0Nf 10 c char 1 " " " " Character char 11 s symbol ` ` varchar 12 p timestamp 8 dateDtimespan 0Np 0Wp Timestamp DateTime (RW) 13 m month 4 2000.01m 0Nm 14 d date 4 2000.01.01 0Nd 0Wd date Date 15 z datetime 8 dateTtime 0Nz 0wz timestamp Timestamp DateTime (RO) 16 n timespan 8 00:00:00.000000000 0Nn 0Wn Timespan TimeSpan 17 u minute 4 00:00 0Nu 0Wu 18 v second 4 00:00:00 0Nv 0Wv 19 t time 4 00:00:00.000 0Nt 0Wt time Time TimeSpan

Columns: n short int returned by type and used for Cast, e.g. 9h$3 c character used lower-case for Cast and upper-case for Tok and Load CSV sz size in bytes inf infinity (no math on temporal types); 0Wh is 32767h

RO: read only; RW: read-write

Other datatypes 20-76 enums 77 anymap 104 projection 78-96 77+t – mapped list of lists of type t 105 composition 97 nested sym enum 106 f' 98 table 107 f/ 99 dictionary 108 f\ 100 lambda 109 f': 101 unary primitive 110 f/: 102 operator 111 f\: 103 iterator 112 dynamic load

Above, f is an applicable value.

Nested types are 77+t (e.g. 78 is boolean. 96 is time.)

Cast $: where char is from the c column above char$data:CHAR$string

dict:`a`b!…
table:([]x:…;y:…)
date.(year month week mm dd)
time.(minute second mm ss)
milliseconds: time mod 1000

Namespaces

`.h` (markup)

HTTP, markup and data conversion.

`.j` (JSON)

De/serialize as JSON.

`.m` (modules)

The currently loaded modules. The meaning of .m has changed between kdb+ versions.

`.Q` (utils)

Utilities: general, environment, IPC, datatype, database, partitioned database state, segmented database state, file I/O, debugging, profiling.

`.z` (environment, callbacks)

Environment, callbacks