Data.Number

fromString :: String -> Maybe Number

Attempt to parse a Number using JavaScripts parseFloat. Returns Nothing if the parse fails or if the result is not a finite number.

Example:

> fromString "123"
(Just 123.0)

> fromString "12.34"
(Just 12.34)

> fromString "1e4"
(Just 10000.0)

> fromString "1.2e4"
(Just 12000.0)

> fromString "bad"
Nothing

Note that parseFloat allows for trailing non-digit characters and whitespace as a prefix:

> fromString "  1.2 ??"
(Just 1.2)

nan :: Number

Not a number (NaN).

> nan
NaN

isNaN :: Number -> Boolean

Test whether a number is NaN.

> isNaN 0.0
false

> isNaN nan
true

infinity :: Number

Positive infinity. For negative infinity use (-infinity)

> infinity
Infinity

> (-infinity)
- Infinity

isFinite :: Number -> Boolean

Test whether a number is finite.

> isFinite 0.0
true

> isFinite infinity
false

> isFinite (-infinity)
false

> isFinite nan
false

abs :: Number -> Number

Returns the absolute value of the argument.

> x = -42.0
> sign x * abs x == x
true

acos :: Number -> Number

Returns the inverse cosine in radians of the argument.

> acos 0.0 == pi / 2.0
true

asin :: Number -> Number

Returns the inverse sine in radians of the argument.

> asin 1.0 == pi / 2.0
true

atan :: Number -> Number

Returns the inverse tangent in radians of the argument.

> atan 1.0 == pi / 4.0
true

atan2 :: Number -> Number -> Number

Four-quadrant tangent inverse. Given the arguments y and x, returns the inverse tangent of y / x, where the signs of both arguments are used to determine the sign of the result. If the first argument is negative, the result will be negative. The result is the angle between the positive x axis and a point (x, y).

> atan2 0.0 1.0
0.0
> atan2 1.0 0.0 == pi / 2.0
true

ceil :: Number -> Number

Returns the smallest integer not smaller than the argument.

> ceil 1.5
2.0

cos :: Number -> Number

Returns the cosine of the argument, where the argument is in radians.

> cos (pi / 4.0) == sqrt2 / 2.0
true

exp :: Number -> Number

Returns e exponentiated to the power of the argument.

> exp 1.0
2.718281828459045

floor :: Number -> Number

Returns the largest integer not larger than the argument.

> floor 1.5
1.0

log :: Number -> Number

Returns the natural logarithm of a number.

> log e
1.0

max :: Number -> Number -> Number

Returns the largest of two numbers. Unlike max in Data.Ord this version returns NaN if either argument is NaN.

min :: Number -> Number -> Number

Returns the smallest of two numbers. Unlike min in Data.Ord this version returns NaN if either argument is NaN.

pow :: Number -> Number -> Number

Return the first argument exponentiated to the power of the second argument.

> pow 3.0 2.0
9.0
> sqrt 42.0 == pow 42.0 0.5
true

remainder :: Number -> Number -> Number

Computes the remainder after division. This is the same as JavaScript's % operator.

Operator alias for Data.Number.remainder (left-associative / precedence 7)

round :: Number -> Number

Returns the integer closest to the argument.

> round 1.5
2.0

sign :: Number -> Number

Returns either a positive or negative +/- 1, indicating the sign of the argument. If the argument is 0, it will return a +/- 0. If the argument is NaN it will return NaN.

> x = -42.0
> sign x * abs x == x
true

sin :: Number -> Number

Returns the sine of the argument, where the argument is in radians.

> sin (pi / 2.0)
1.0

sqrt :: Number -> Number

Returns the square root of the argument.

> sqrt 49.0
7.0

tan :: Number -> Number

Returns the tangent of the argument, where the argument is in radians.

> tan (pi / 4.0)
0.9999999999999999

trunc :: Number -> Number

Truncates the decimal portion of a number. Equivalent to floor if the number is positive, and ceil if the number is negative.

ceil 1.5
2.0

e :: Number

The base of the natural logarithm, also known as Euler's number or e.

> log e
1.0

> exp 1.0 == e
true

> e
2.718281828459045

ln2 :: Number

The natural logarithm of 2.

> log 2.0 == ln2
true

> ln2
0.6931471805599453

ln10 :: Number

The natural logarithm of 10.

> log 10.0 == ln10
true

> ln10
2.302585092994046

log10e :: Number

Base 10 logarithm of e.

> 1.0 / ln10 - log10e
-5.551115123125783e-17

> log10e
0.4342944819032518

log2e :: Number

The base 2 logarithm of e.

> 1.0 / ln2 == log2e
true

> log2e
1.4426950408889634

pi :: Number

The ratio of the circumference of a circle to its diameter.

> pi
3.141592653589793

sqrt1_2 :: Number

The square root of one half.

> sqrt 0.5 == sqrt1_2
true

> sqrt1_2
0.7071067811865476

sqrt2 :: Number

The square root of two.

> sqrt 2.0 == sqrt2
true

> sqrt2
1.4142135623730951

tau :: Number

The ratio of the circumference of a circle to its radius.

> 2.0 * pi == tau
true

> tau
6.283185307179586