Rich H.H.J reference card.V6.01.2006

Arithmetic Dyads

J Reference Card for version 6.01

if f is [:

result

result

2

+ 8

Plus

10

Arithmetic Monads

its output

2

- 8

Minus

_6

<. 4.5

Floor

4

Legend

is omitted

g

( f

2

* 8

Times

16

>. 4.5

Ceiling

5

x y args to verbs

( f

h )

g )

2

% 8

Divide

0.25

2

| 8

Residue

0

* _4 0 3 Sign

_1 0 1

m n nouns

x

Fork

y

x Hook

y

! 4

Factorial

24

u v verbs

2

^ 8

Exponent

256

? 20

Random in i. y 7

italics optional

2

^. 8

Log

3

Assignments

3

%: 8

Root

2

? 0

Random in (0,1) 0.452

(n) =. v

AssignInd: value of n

2

>. 6

Greater

6

Comparisons (result 1 if TRUE)

gives name(s) to assign

2

<. 6

Lesser

2

=

Equal

>

Greater

>: GreaterOrEqual

'n1 n2' =. v1;v2

AssignMult: one level

abcd

36 +. 24

GCD

12

~:

NotEqual

<

Less

<: LessOrEqual

of boxing is removed

36 *. 24

LCM

72

-:

Match (rank _ _): equal in shape, boxing, and values;

'`add sub' =. +`-

AssignAR

efgh

10 10 #. 8 3 Base

83

but if empty, type does not matter

ijkl

10 10 #: 83

Antibase

8 3

Selections

A is

mnop

're' E.'reread'

WindowedMatch

1 0 1 0 0 0

2

! 8

CombOutOf 28

(ranks may be > 1)

1 0 2 # 'abc' Copy

acc

2

? 8

Deal

4 2

1j1 0 2 # 'abc' CopyFill

a cc

Comparisons are tolerant; follow by !.0 for exact comparison

1j1 0 2 #!.'*' 'abc' CopyCustom

a*cc

Shorthands

Searches

1 0 1^:_1 'ab' Expand

a b

'people' i. 'pow'

IndexOf1

0 2 6

<: 5

y-1

Decrement

4

Increment

'people' i: 'pow'

IndexOfLast1

3 2 6

1 0 1^:_1!.'*' 'ab' ExpandCustom

a*b

>: 5

y+1

6

'pow' e. 'people'

ElementOf

1

1 1 0

mnop

% 5

1%y

Reciprocal

0.2

_1 1 { A ItemsFrom

-. 0.3

1-y

Complement

0.7

I. 0 1 1 0 1

IndicesOfOnes

1 2 4

Monad

efgh

Double

0 2 4 I. 2 3 _1 9

FindInsertionPoint12

1 2 0 3

i. & i:

bd

+: 9

y*2

Halve

18

IndexOfLargest

34

i. 3

-: 9

y%2

4.5

(i. >./) 1 2 8 5

2

1 3 {"1 A FromEachRow

fh

*: 9

y^2

Square

81

3 (= i. 1:) 1 3 3 0 FindFirstTrue456

67

1

0 1 2

jl

%:

2%y

SquareRoot

3

3 ([: I. =)

1 3 3 0 IndicesWhereTrue

1 2

i. _3

np

^ 1

e

^y

Exp

2.718

m&i.

e.&n

m&i:

FastSearch (when used repeatedly)

2 1 0

{ A

From (All axes

j

1 rank searched for is rank of items of other operand

2 min index

i. 2 3

2 1

^. 7.389

e^.y NaturalLog

2

3

4

5

scalar)

#. 1 0 1

2#.y FromBase2

5

before which item can be inserted in order

or <.

or i:

or 0:

0 1 2

From (Omitted

efgh

#: 5

2#:y ToBase2*

1 0 1

6 any comp. or e.

Operations on Ordered Sets

3 4 5

1 3

{ A

i: 2

trailing axis)

mnop

m.^:_1

m#:y ToBasem*

7 or +/ +./ *./

'rare'-. 'er'

RemoveItems

a

*ToBase2 and ToBasem produce as many

~. 'rare'

UniqueItems

rae

_1 0 1

1

2

From (Axis 1

result items as needed to hold significance

~: 'rare'

UniqueSieve

1 1 0 1

{ A complementary) efh

Operations on Booleans

i.~ 'rare'

SelfClassify

0 1 0 3

From (General

feg

16b1a

Base16 constant

26

Join and Reshape

1 3

1 0 2

{ A axes)

nmo

Dyads

Monad: -. NOT

ab

+.

OR

,

Enfile

abcd

ca

*.

AND

=

XOR

cd

+:

NOR

*:

NAND

~: XNOR

'ab' , 'cd'

abcd

From (Omitted

ge

Append

(<a:;2 0) { A early axis)

ki

> < >: <: are also meaningful

0 1

Append

0 1

om

m b.

(0≤m<16) Boolean function with truth

, 8 9

(unequal

2 3

1 1

FromUnboxed

table

(

is AND)

2 3

2 2#:4 4#:m 1 b.

ranks)

8 9

3 2 (<"1@[ { ]) A

(fast form)

fo

m b.

(16≤m<32) bitwise Boolean; applies

0

1

(m-16) b. to each bit of integers

0 1

, ,8

Append

Whole-Array Operations

2 3

x 32 b. y

x 33 b. y

x 34 b. y

2 3

(short)

|. 'abcde'

Reverse

edcba

rotate y left x bits

unsigned

signed

8 0

2 |. 'abcde'

RotateLeft

cdeab

shift L (x>0) or

R (x<0) x bits

0 1

, 8

Append

0 1

_2 |. 'abcde'

RotateRight

deabc

2 3

(atom)

2 3

2 |.!.'*' 'abcde'

ShiftLeft

cde**

Take and Drop