Float

Functions for working with floating point numbers.

Summary

Functions

ceil(number, precision \\ 0): Rounds a float to the smallest integer greater than or equal to num
floor(number, precision \\ 0): Rounds a float to the largest integer less than or equal to num
parse(binary): Parses a binary into a float
round(number, precision \\ 0): Rounds a floating point value to an arbitrary number of fractional digits (between 0 and 15)
to_charlist(float): Returns a charlist which corresponds to the text representation of the given float
to_string(float): Returns a binary which corresponds to the text representation of the given float

Functions

ceil(number, precision \\ 0)

ceil(float, 0..15) :: float

Rounds a float to the smallest integer greater than or equal to num.

ceil/2 also accepts a precision to round a floating point value down to an arbitrary number of fractional digits (between 0 and 15).

This function always returns floats. Kernel.trunc/1 may be used instead to truncate the result to an integer afterwards.

Examples

iex> Float.ceil(34.25)
35.0

iex> Float.ceil(-56.5)
-56.0

iex> Float.ceil(34.251, 2)
34.26

floor(number, precision \\ 0)

floor(float, 0..15) :: float

Rounds a float to the largest integer less than or equal to num.

floor/2 also accepts a precision to round a floating point value down to an arbitrary number of fractional digits (between 0 and 15).

This function always returns a float. Kernel.trunc/1 may be used instead to truncate the result to an integer afterwards.

Examples

iex> Float.floor(34.25)
34.0

iex> Float.floor(-56.5)
-57.0

iex> Float.floor(34.259, 2)
34.25

parse(binary)

parse(binary) :: {float, binary} | :error

Parses a binary into a float.

If successful, returns a tuple in the form of {float, remainder_of_binary}; when the binary cannot be coerced into a valid float, the atom :error is returned.

If the size of float exceeds the maximum size of 1.7976931348623157e+308, the ArgumentError exception is raised.

If you want to convert a string-formatted float directly to a float, String.to_float/1 can be used instead.

Examples

iex> Float.parse("34")
{34.0, ""}

iex> Float.parse("34.25")
{34.25, ""}

iex> Float.parse("56.5xyz")
{56.5, "xyz"}

iex> Float.parse("pi")
:error

round(number, precision \\ 0)

round(float, 0..15) :: float

Rounds a floating point value to an arbitrary number of fractional digits (between 0 and 15).

This function only accepts floats and always returns a float. Use Kernel.round/1 if you want a function that accepts both floats and integers and always returns an integer.

Examples

iex> Float.round(5.5674, 3)
5.567

iex> Float.round(5.5675, 3)
5.568

iex> Float.round(-5.5674, 3)
-5.567

iex> Float.round(-5.5675, 3)
-5.568

iex> Float.round(-5.5675)
-6.0

to_charlist(float)

to_charlist(float) :: charlist

Returns a charlist which corresponds to the text representation of the given float.

It uses the shortest representation according to algorithm described in “Printing Floating-Point Numbers Quickly and Accurately” in Proceedings of the SIGPLAN ‘96 Conference on Programming Language Design and Implementation.

Examples

iex> Float.to_charlist(7.0)
'7.0'

to_string(float)

to_string(float) :: String.t

Returns a binary which corresponds to the text representation of the given float.

Examples

iex> Float.to_string(7.0)
"7.0"