View Source Integer (Elixir v1.12.2)
Functions for working with integers.
Some functions that work on integers are found in Kernel
:
Link to this section Summary
Functions
Returns the ordered digits for the given integer
.
Returns the extended greatest common divisor of the two given integers.
Performs a floored integer division.
Returns the greatest common divisor of the two given integers.
Computes the modulo remainder of an integer division.
Parses a text representation of an integer.
Computes base
raised to power of exponent
.
Returns a charlist which corresponds to the text representation
of integer
in the given base
.
Returns a binary which corresponds to the text representation
of integer
in the given base
.
Returns the integer represented by the ordered digits
.
Link to this section Guards
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
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
Link to this section Functions
@spec 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]
@spec 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}
@spec 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
@spec 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
@spec 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
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
@spec 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
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'
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"
@spec 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