int
>>> dir(int)
['__abs__', '__add__', '__and__', '__bool__', '__ceil__', '__class__', '__delattr__', '__dir__', '__divmod__', '__doc__', '__eq__', '__float__', '__floor__', '__floordiv__', '__format__', '__ge__', '__getattribute__', '__getnewargs__', '__gt__', '__hash__', '__index__', '__init__', '__init_subclass__', '__int__', '__invert__', '__le__', '__lshift__', '__lt__', '__mod__', '__mul__', '__ne__', '__neg__', '__new__', '__or__', '__pos__', '__pow__', '__radd__', '__rand__', '__rdivmod__', '__reduce__', '__reduce_ex__', '__repr__', '__rfloordiv__', '__rlshift__', '__rmod__', '__rmul__', '__ror__', '__round__', '__rpow__', '__rrshift__', '__rshift__', '__rsub__', '__rtruediv__', '__rxor__', '__setattr__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__truediv__', '__trunc__', '__xor__', 'as_integer_ratio', 'bit_count', 'bit_length', 'conjugate', 'denominator', 'from_bytes', 'imag', 'numerator', 'real', 'to_bytes']
Definition
An int (integer) is a positive or negative whole number or 0. If a number has a trailing decimal . it is a float, even if there are no digits trailing the decimal point. Python's integers can be as large as your computer's memory allows.
>>> type(42)
<class 'int'>
>>> type(42.)
<class 'float'>
>>> type(42.0)
<class 'float'>
Basic operations on integers
Arithmetic operations
# addition
>>> 10 + 3
13
# subraction
>>> 10 - 3
7
# multiplication
>>> 10 * 3
30
# division (always returns a float)
>>> 10 / 3
3.3333333333333335
# floor division
>>> 10 // 3
3
# modulus
>>> 10 % 3
1
# exponent
>>> 10 ** 3
1000
Incrementing and immutability
Integers can be incremented by any artimetic operator. However, since integers are immutable a variable must be used to use these incrementing operations.
>>> a = 5
>>> a += 3 # 8
>>> a *= 3 # 24
>>> a **= 2 # 576
>>> a %=6 # 0
>>> 5 *= 2
File "<stdin>", line 1
5 *= 2
^
SyntaxError: 'literal' is an illegal expression for augmented assignment
Comparison operations
Comparison operations return a boolean value.
# check equality
>>> 5 == 8
False
# check not equal to
>>> 5 != 8
True
# greater than
>>> 5 > 8
False
# less than
>>> 5 < 8
True
# greater than or equal to
>>> 5 >= 8
False
# less than or equal to
>>> 5 <= 8
True
Boolean values
All integers have truthy boolean values except for 0 which has a falsy value.
>>> bool(1)
True
>>> bool(-50)
True
>>> bool(0)
False
Readability
Underscores can be added to integers to improve their readability. This does not affect the value of the integer.
>>> 1_000 * 5
5000
>>> 1_234_567 + 13
1234580
Dunder methods
| Dunder Method | Operation | Example (normal syntax) | Example (dunder call) |
|---|---|---|---|
__add__ | Addition | 3 + 4 → 7 | (3).__add__(4) |
__sub__ | Subtraction | 7 - 2 → 5 | (7).__sub__(2) |
__mul__ | Multiplication | 3 * 2 → 6 | (3).__mul__(2) |
__truediv__ | Division | 7 / 2 → 3.5 | (7).__truediv__(2) |
__floordiv__ | Floor division | 7 // 2 → 3 | (7).__floordiv__(2) |
__mod__ | Modulo | 7 % 2 → 1 | (7).__mod__(2) |
__pow__ | Exponentiation | 2 ** 3 → 8 | (2).__pow__(3) |
__neg__ | Negation | -5 → -5 | (5).__neg__() |
__pos__ | Unary plus | +5 → 5 | (5).__pos__() |
__abs__ | Absolute value | abs(-3) → 3 | (-3).__abs__() |
__eq__ | Equality | 3 == 3 → True | (3).__eq__(3) |
__lt__ | Less than | 2 < 5 → True | (2).__lt__(5) |
__int__ | Convert to int | int(3.0) → 3 | (3.0).__int__() |
__float__ | Convert to float | float(3) → 3.0 | (3).__float__() |
__hash__ | Hash value | hash(3) | (3).__hash__() |
__index__ | Used for indexing | [10,20,30][True] → 20 | (1).__index__() |
int methods and attributes
as_integer_ratio
Returns a number as a fraction represented by a tuple. The first number is the numerator of the fraction and the second number is the denominator.
>>> (10).as_integer_ratio()
(10, 1)
>>> (10.5).as_integer_ratio()
(21, 2)
# converting a decimal to fraction and back again
>>> x = (44.8).as_integer_ratio()
>>> x[0] / x[1]
44.8
bit_count
Returns the number of 1 bits consumed by an integer when observed in binary. Below the examples are using bin to display the number in binary form.
>>> bin(0)
'0b0'
>>> (0).bit_count()
0
>>> bin(2)
'0b10'
>>> (2).bit_count()
1
>>> bin(3)
'0b11'
>>> (3).bit_count()
2
>>> bin(15)
'0b1111'
>>> (15).bit_count()
4
bit_length
Returns the total number of bits (1's and 0's) required to represent the intger in binary.
>>> bin(0)
'0b0'
>>> (0).bit_length()
0
>>> bin(1)
'0b1'
>>> (1).bit_length()
1
>>> bin(15)
'0b1111'
>>> (15).bit_length()
4
>>> bin(16)
'0b10000'
>>> (16).bit_length()
5
conjugate
Returns the complex conjugate of a number. While integers don't have an complex portion the method exists for all number types.
>>> (5).conjugate()
5
>>> (-9).conjugate()
-9
denominator
Returns the denominator of the integer. While integers always have a denominator of 1 the attribute exists for multiple number types.
>>> (5).denominator
1
>>> (10).denominator
1
>>> (-33).denominator
1
from_bytes
Returns an interger from a sequence of bytes. It is the inverse of to_bytes.
syntax:
int.from_bytes(bytes, byteorder, signed=False)
imag
Returns the complex (imaginary) portion of an integer. While integers don't have an complex portion the method exists for all number types.
>>> (5).imag
0
numerator
Returns the numerator of the integer. While integers always have a numerator of the number itself the attribute exists for multiple number types.
>>> (5).numerator
5
>>> (-19).numerator
-19
real
Returns the real portion of an integer. While integers don't have an complex portion the method exists for all number types.
>>> (55).real
55