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Tutorial	Intro Screencast K 99: Ninety Nine K Problems Tutorial Verbs-Classification
Project Euler Code Golf:	Project Euler Code Golf
Project Coding Guidelines:	Coding Guidelines
List of idioms:	Idioms
Dictionaries:	Dictionaries
Strings:	Strings
Data and Execution:	Data and Execution
Primitive Operations	Primitive Operations
C Reference	C Reference
Examples	Examples
Memory Management	Memory Management
Amend	Amend
Random Lines of K	gist
Replicating SQL functionality	Replicating SQL functionality
shared library	shared library
more Memory management	newK, unpool, repool, kap
csv loading	csv loading and dictionary

Links

hakank’s K/Kona Page
Whitney on K
No Stinking Loops
Remarks on Style
K by example
K as a Prototyping Language
K on Rosetta Code
Kx Corporate Website
Kx K Examples
Gordon Baker’s Q site
Milan Ondrus’s KDB+ site
Introduction to K
kdbfaq blog
K 2.0 Reference Card [PDF]
FinnAPL Idioms
kdb faq on thalesians
Q for Mortals Book on Amazon
K 2.0 User Manual
K 2.0 Reference Manual
K 2.0 C-K Interface Manual
A+
J
kOS

Screencasts

Introduction to K
MapReduce in K

Off-site user groups

LinkedIn Group: [Kx] Technology Network [Jobs]
LinkedIn Group: KDB+/Q User Group
LinkedIn Group: Kx/KDB+ Networking Forum [Jobs]
Kx’s KDB+ Personal Developers Google Group

Helpful Commands

Command	What It Does
\	Shows ‘Help’
.`	Shows the full K-Tree

Verbs

Verb	Monadic	Dyadic	Triadic	Tetradic
+	flip	plus
–	negate	minus
*	first	times
%	reciprocal	divide
|	reverse	max_or
&	where	min_and
^	shape	power
!	enumerate	rotate_mod
<	grade up	less_than
>	grade down	greater_than
=	group	equals
~	not/attribute	match
@	atom	at index	amend/trap	amend
?	range	function inverse/find/draw/deal/sample	invert-guess
_	floor (tolerant)	drop_cut
,	enlist	join
#	count	take_reshape
$	format	dollar
.	dot/monadic/make/unmake	dot index	amend/trap	amend
:	colon/monadic	colon/dyadic

Adverbs

Adverb	Definition
/	over
\	scan
’	each
/:	each right
\:	each left
’:	eachpair

Input/Output Verbs

Verb	Monadic	Dyadic
0:	read text file.	write text file
	read from stdin until EOF (empty symbol).	write to stdout if first param is an empty symbol ( `0:stuff_to_print )
1:	read binary file (mmapped)	write binary file
2:	read binary file (copied to memory)	dll function call
3:	open handle/close handle	asynchronous send
4:	type of data	synchronous send
5:	printed representation	append to binary file
6:	read raw byte string	write raw byte string

Control Flow / Conditionals

Name	Use	Example
:	:[\(cond_1;ret_1;cond_2;ret_2;\ldots;cond_n;ret_n;ret_{else}\)]	not_x: :[0=x;1;0]
if	if[\(cond;exp_1;exp_2;\ldots;exp_n\) ]	if[n!2; n:1+3*n; `0:"n was odd\n"]
while	while[\(cond; exp_1; exp_2;\ldots;exp_n \) ]	while[~a!2; a %: 2; `0:"dividing\n"]
do	do[\(n;exp_1;exp_2;\ldots;exp_m\)]	do[4; `0:"******\n"]

Commands

Command	Definition
\	show help
\p [n]	[set] print precision
\r [seed]	[set] random seed
\+	print operator reference
\l [script]	load k script
\s [script]	step k script
\t [code]	time execution (in ms)

Reserved Words

All reserved words start with a leading underscore(_)

Constants

Name	Definition
_T	[current UTC Julian day count]+[fraction complete] (K epoch is 2035-01-01T00:00:00)
_a	program argument vector (argv)
_d	K-Tree path / current working dictionary
_f	anonymous reference to current function
_h	host name
_i
_k
_m
_n	nil
_p
_s
_t	current UTC time (int) (K epoch is 2035-01-01T00:00:00)
_u
_v
_w

Monadic Verbs

Name	Definition
_acos	inverse cosine
_asin	inverse sine
_atan	inverse tangent
_ceil	ceiling (intolerant)
_ceiling	ceiling (tolerant)
_cos	cosine
_cosh	hyperbolic cosine
_exp	exponential
_floor	largest previous integer (intolerant)
_log	natural logarithm
_sin	sine
_sinh	hyperbolic sine
_sqr	square
_sqrt	square root
_tan	tangent
_tanh	hyperbolic tangent
_abs	absolute value
_bd	convert to binary representation
_ci	char-of-int (octal if unprintable char)
_db	construct from binary representation
_dj	date from Julian day count
_exit	exit with status x
_getenv	get an environment variable
_gtime	in UTC, ints: YYYMMDD,HHMMSS (_gtime _t)
_host	host name IP address (int)
_ic	int-of-char
_inv	inverse of a matrix
_jd	Julian day count from date _jd 20110315
_lt	convert output of _t to local time
_ltime	localized version of _gtime
_size	size of file (bytes)

Dyadic Verbs

Name	Definition
_bin	index of element using binary search
_binl	search for several elements
_di	delete element at index
_dot	dot product
_draw	draw x random numbers from 0 to y-1 (compare: ?)
_dv	delete value
_dvl	delete several values
_in	true if x is in y
_lin	_in for several values
_lsq	matrix division
_mul	matrix multiplication
_setenv	set environment variable
_sm	string match
_ss	positions of substring y in string x
_sv	scalar from vector with base change
_vs	vector from scalar with base change

Triadic Verbs

Name	Definition
_ssr	string search & replace

Command-line Arguments

Name	Definition
-h (int)	open an HTTP port
-i (int)	open an IPC port
-e (string)	execute a string
-x (string)	execute a string and print
[file]	execute a script (as in ./k script.k, extension optional)