A copy of k.txt, for the K programming language. The reference card has not been available online under the original link for a few years. See also Primitives on the K language wiki.
k has atom, list (2;`c), dict `a`b!(2;`c) and func {[x;y]x+y}.
20 primitives/verbs, 6 operators/adverbs and 3 system functions.
Verb (unary) Adverb Noun (null)
: gets ' each name `a`b `
+ plus flip / over|join char "ab" " "
- minus negate \ scan|split int 2 34 0N(nan)
* times first ': eachprior float 2 .3 0n(nan) 0w(inf)
% divide sqrt /: eachright date 2016.06.28 (.z.d)
! mod|map enum|key \: eachleft time 12:34:56.789 (.z.t)
& min|and where
| max|or reverse System list (2;3.4;`ab)
< less asc 0: file r/w(line) dict `a`b!(2;`c)
> more desc 1: file r/w(byte) view f::32+1.8*c TODO
= equal group 2: open/msg/close func {[c]32+1.8*c}
~ match not
, concat enlist
^ except null \t:n x time
# take|rsh count #[t;c;b[;a]] select \l a.k load
_ drop|cut floor \w workspace
$ cast|sum string $[c;t;f] COND \v variables
? find|rnd distinct ?[x;I;[f;]y] insert \f functions
@ at type @[x;i;[f;]y] amend \a ancestors
. dot eval|val .[x;i;[f;]y] dmend \d directory
atoms are ncif(name char int float) and mdhrst(month day hour min sec milli)
vector is unitype list of atoms, e.g. (2;3) is 2 3 and ("a";"b") is "ab"
matrix is uniform list of vectors, e.g. m:(0 1 2;1 2 3)
atomic functions (+-*%!&|<>=$;-%~_^$) penetrate, e.g. 2 3+m is (2 3 4;4 5 6)
default function parameters are x y z, e.g. {z+x*y}[3;2;1] is 7
indexing and function call use []'s, e.g. m[1;2] is {x+y}[1;2] is 3
no precedence among verbs: 2*4-3 is 2* 4- 3 is 2
grammar: E:E;e|e e:nve|te| t:n|v v:tA|V n:t[E]|(E)|{E}|N
unary list needs ",", e.g. 2(atom) ,2(list)
unary verb arg needs ":", e.g. #'(take each) #:'(count each)
unary call doesn't need []'s, e.g. f x is f[x]
datetime: 2016.06.28+3 week:7*-7!d bar5:5*-5!r etc.
generate: !n(enum) !N(odometer) ?n(uniform) ?-n(normal) n?(draw) -n?(deal) =n(identity matrix)
0:""0:"prompt" /readline writeline
/ comment
\ exit
on error(inspect locals etc.)
> ' up
> \ out
2+ \3 trace
while(c){..};if(c){..}
exp log sin cos [x]cmb;in within
count first last sum min max;[x]avg [x]var [x]dev
TODO: parallel/mapreduce
f':jobs / across machine
handles 2:jobs / across cluster
LIMITS: names8 params8 locals8 globals16 constants128 jump256 v[i]:m[i;j] {z}'/\