q types

abstract

Data types for the q language are listed here.

q datatypes
n	char	name	bytes	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` or `0`	`0Nj` or `0N`	`0Wj` or `0W`	bigint	Long	int64
8	e	real	4	`0e`	`0Ne`	`0We`	real	Float	single
9	f	float	8	`0.0` or `0f`	`0n`	`0w`	float	Double	double
10	c	char	1	`" "`	`" "`			Character	char
11	s	symbol	.	`	`		varchar	String	string
12	p	timestamp	8	dateDtimespan	`0Np`	`0Wp`		Timestamp	DateTime (read)
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 (read-only)
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`	`0Nv`
19	t	time	4	`00:00:00.000`	`0Nt`	`0Wt`	time	Time	TimeSpan
20-76		enums
77		anymap
78-96		mapped list of lists of type `(n - 77)`
97		nested sym enum
98		table
99		dictionary
100		lambda
101		unary primitive
102		operator
103		iterator
104		projection
105		composition
106		`v'` (each)
107		`v/` (over)
108		`v\` (scan)
109		`v':` (each prior)
110		`v/:` (each right)
111		`v\:` (each left)
112		dynamic load

Atoms have negative types. Lists have positive types.

q)type 23
-7h
q)type enlist 23
7h
q)type 1,2,3,4,5
7h
q)type (1;2;3;4;5)
7h
q)type each 1,2,3,4,5
-7 -7 -7 -7 -7h

A string is a list of chars.

q)type "Hello, World!"
10h

Cast a string as a symbol.

q)` $ "Hello, World!"
`Hello, World!
q)-11h $ "Hello, World!"
`Hello, World!

Convert a list of symbols to a list of strings.

q)type `one`two`three`four`five
11h
q)type string `one`two`three`four`five
0h
q)string `one`two`three`four`five
"one"
"two"
"three"
"four"
"five"