Reference card
Note
Want a quick and handy q reference resource? Download the q Cheat Sheet (PDF download).
Keywords
By category
.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 | ||||||
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
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
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 |
Command-line options, System commands, OS commands
Datatypes
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