Integer
Functions for working with integers.
Some functions that work on integers are found in Kernel
:
Summary
Guards
- is_even(integer)
Determines if an
integer
is even.- is_odd(integer)
Determines if
integer
is odd.
Functions
- digits(integer, base \\ 10)
Returns the ordered digits for the given
integer
.- extended_gcd(n, n)
Returns the extended greatest common divisor of the two given integers.
- floor_div(dividend, divisor)
Performs a floored integer division.
- gcd(integer1, integer2)
Returns the greatest common divisor of the two given integers.
- mod(dividend, divisor)
Computes the modulo remainder of an integer division.
- parse(binary, base \\ 10)
Parses a text representation of an integer.
- pow(base, exponent)
Computes
base
raised to power ofexponent
.- to_charlist(integer, base \\ 10)
Returns a charlist which corresponds to the text representation of
integer
in the givenbase
.- to_string(integer, base \\ 10)
Returns a binary which corresponds to the text representation of
integer
in the givenbase
.- undigits(digits, base \\ 10)
Returns the integer represented by the ordered
digits
.
Guards
is_even(integer)Source
Determines if an integer
is even.
Returns true
if the given integer
is an even number, otherwise it returns false
.
Allowed in guard clauses.
Examples
iex> Integer.is_even(10) true iex> Integer.is_even(5) false iex> Integer.is_even(-10) true iex> Integer.is_even(0) true
is_odd(integer)Source
Determines if integer
is odd.
Returns true
if the given integer
is an odd number, otherwise it returns false
.
Allowed in guard clauses.
Examples
iex> Integer.is_odd(5) true iex> Integer.is_odd(6) false iex> Integer.is_odd(-5) true iex> Integer.is_odd(0) false
Functions
digits(integer, base \\ 10)Source
Specs
digits(integer(), pos_integer()) :: [integer(), ...]
Returns the ordered digits for the given integer
.
An optional base
value may be provided representing the radix for the returned digits. This one must be an integer >= 2.
Examples
iex> Integer.digits(123) [1, 2, 3] iex> Integer.digits(170, 2) [1, 0, 1, 0, 1, 0, 1, 0] iex> Integer.digits(-170, 2) [-1, 0, -1, 0, -1, 0, -1, 0]
extended_gcd(n, n)Source
Specs
extended_gcd(integer(), integer()) :: {non_neg_integer(), integer(), integer()}
Returns the extended greatest common divisor of the two given integers.
It uses the Extended Euclidean algorithm to return a three-element tuple with the gcd
and the coefficients m
and n
of Bézout's identity such that:
gcd(a, b) = m*a + n*b
By convention, extended_gcd(0, 0)
returns {0, 0, 0}
.
Examples
iex> Integer.extended_gcd(240, 46) {2, -9, 47} iex> Integer.extended_gcd(46, 240) {2, 47, -9} iex> Integer.extended_gcd(-46, 240) {2, -47, -9} iex> Integer.extended_gcd(-46, -240) {2, -47, 9} iex> Integer.extended_gcd(14, 21) {7, -1, 1} iex> Integer.extended_gcd(10, 0) {10, 1, 0} iex> Integer.extended_gcd(0, 10) {10, 0, 1} iex> Integer.extended_gcd(0, 0) {0, 0, 0}
floor_div(dividend, divisor)Source
Specs
floor_div(integer(), neg_integer() | pos_integer()) :: integer()
Performs a floored integer division.
Raises an ArithmeticError
exception if one of the arguments is not an integer, or when the divisor
is 0
.
Integer.floor_div/2
performs floored integer division. This means that the result is always rounded towards negative infinity.
If you want to perform truncated integer division (rounding towards zero), use Kernel.div/2
instead.
Examples
iex> Integer.floor_div(5, 2) 2 iex> Integer.floor_div(6, -4) -2 iex> Integer.floor_div(-99, 2) -50
gcd(integer1, integer2)Source
Specs
gcd(integer(), integer()) :: non_neg_integer()
Returns the greatest common divisor of the two given integers.
The greatest common divisor (GCD) of integer1
and integer2
is the largest positive integer that divides both integer1
and integer2
without leaving a remainder.
By convention, gcd(0, 0)
returns 0
.
Examples
iex> Integer.gcd(2, 3) 1 iex> Integer.gcd(8, 12) 4 iex> Integer.gcd(8, -12) 4 iex> Integer.gcd(10, 0) 10 iex> Integer.gcd(7, 7) 7 iex> Integer.gcd(0, 0) 0
mod(dividend, divisor)Source
Specs
mod(integer(), neg_integer() | pos_integer()) :: integer()
Computes the modulo remainder of an integer division.
Integer.mod/2
uses floored division, which means that the result will always have the sign of the divisor
.
Raises an ArithmeticError
exception if one of the arguments is not an integer, or when the divisor
is 0
.
Examples
iex> Integer.mod(5, 2) 1 iex> Integer.mod(6, -4) -2
parse(binary, base \\ 10)Source
Specs
parse(binary(), 2..36) :: {integer(), remainder_of_binary :: binary()} | :error
Parses a text representation of an integer.
An optional base
to the corresponding integer can be provided. If base
is not given, 10 will be used.
If successful, returns a tuple in the form of {integer, remainder_of_binary}
. Otherwise :error
.
Raises an error if base
is less than 2 or more than 36.
If you want to convert a string-formatted integer directly to an integer, String.to_integer/1
or String.to_integer/2
can be used instead.
Examples
iex> Integer.parse("34") {34, ""} iex> Integer.parse("34.5") {34, ".5"} iex> Integer.parse("three") :error iex> Integer.parse("34", 10) {34, ""} iex> Integer.parse("f4", 16) {244, ""} iex> Integer.parse("Awww++", 36) {509216, "++"} iex> Integer.parse("fab", 10) :error iex> Integer.parse("a2", 38) ** (ArgumentError) invalid base 38
pow(base, exponent)Source
Specs
pow(integer(), non_neg_integer()) :: integer()
Computes base
raised to power of exponent
.
Both base
and exponent
must be integers. The exponent must be zero or positive.
See Float.pow/2
for exponentiation of negative exponents as well as floats.
Examples
iex> Integer.pow(2, 0) 1 iex> Integer.pow(2, 1) 2 iex> Integer.pow(2, 10) 1024 iex> Integer.pow(2, 11) 2048 iex> Integer.pow(2, 64) 0x10000000000000000 iex> Integer.pow(3, 4) 81 iex> Integer.pow(4, 3) 64 iex> Integer.pow(-2, 3) -8 iex> Integer.pow(-2, 4) 16 iex> Integer.pow(2, -2) ** (ArithmeticError) bad argument in arithmetic expression
to_charlist(integer, base \\ 10)Source
Specs
to_charlist(integer(), 2..36) :: charlist()
Returns a charlist which corresponds to the text representation of integer
in the given base
.
base
can be an integer between 2 and 36. If no base
is given, it defaults to 10
.
Inlined by the compiler.
Examples
iex> Integer.to_charlist(123) '123' iex> Integer.to_charlist(+456) '456' iex> Integer.to_charlist(-789) '-789' iex> Integer.to_charlist(0123) '123' iex> Integer.to_charlist(100, 16) '64' iex> Integer.to_charlist(-100, 16) '-64' iex> Integer.to_charlist(882_681_651, 36) 'ELIXIR'
to_string(integer, base \\ 10)Source
Specs
to_string(integer(), 2..36) :: String.t()
Returns a binary which corresponds to the text representation of integer
in the given base
.
base
can be an integer between 2 and 36. If no base
is given, it defaults to 10
.
Inlined by the compiler.
Examples
iex> Integer.to_string(123) "123" iex> Integer.to_string(+456) "456" iex> Integer.to_string(-789) "-789" iex> Integer.to_string(0123) "123" iex> Integer.to_string(100, 16) "64" iex> Integer.to_string(-100, 16) "-64" iex> Integer.to_string(882_681_651, 36) "ELIXIR"
undigits(digits, base \\ 10)Source
Specs
undigits([integer()], pos_integer()) :: integer()
Returns the integer represented by the ordered digits
.
An optional base
value may be provided representing the radix for the digits
. Base has to be an integer greater than or equal to 2
.
Examples
iex> Integer.undigits([1, 2, 3]) 123 iex> Integer.undigits([1, 4], 16) 20 iex> Integer.undigits([]) 0
© 2012 Plataformatec
Licensed under the Apache License, Version 2.0.
https://hexdocs.pm/elixir/1.12.0/Integer.html