Python 3
In Python 3, this question doesn't apply. The plain int
type is unbound.
However, you might actually be looking for information about the current interpreter's word size, which will be the same as the machine's word size in most cases. That information is still available in Python 3 as sys.maxsize
, which is the maximum value representable by a signed word. Equivalently, it's the size of the largest possible list or in-memory sequence.
Generally, the
maximum value representable by an unsigned word will be sys.maxsize * 2 + 1
, and the number of bits in a word will be math.log2[sys.maxsize * 2 + 2]
. See this answer for more information.
Python 2
In Python 2, the maximum value for plain int
values is available as sys.maxint
:
>>> sys.maxint
9223372036854775807
You can calculate the minimum value with -sys.maxint - 1
as shown here.
Python seamlessly switches from plain to long integers once you exceed this value. So most of the time, you won't need to know it.
In Python3,
int
has no max limit.
Python2 has two integer types, int
and long
, but Python3 has only int
. int
in Python3 is equivalent to long
in Python2, and there is no max limit. You can handle as large value as memory is available.
This article describes the following contents.
int
andlong
in Python2int
in Python3 has no max limit
See the following article for the maximum and minimum values of the
floating-point number float
.
- Maximum and minimum float values in Python
Note that NumPy uses data types with a fixed number of bits, such as int32
[32-bit integer] and int64
[64-bit integer].
- NumPy: Cast ndarray to a specific dtype with astype[]
int and long in Python2
Python2 has two integer types, int
and long
.
- 5.4 Numeric Types — int, float, long, complex — Python 2.7.18 documentation
You can get the max value of int
with sys.maxint
. The min value [the largest negative value] is -sys.maxint-1
.
- 28.1. sys.maxint — System-specific parameters and functions — Python 2.7.18 documentation
sys.maxint
is at least 2**31-1
, and on a 64-bit environment, it is 2**63-1
.
long
has no maximum and minimum limit.
int in Python3 has no max limit
int
in Python3 corresponds to long
in Python2, and there is no max and min limit.
The sys.maxint constant was removed, since there is no longer a limit to the value of integers. However, sys.maxsize can be used as an integer larger than any practical list or string index. It conforms to the implementation’s “natural” integer size and is typically the same as sys.maxint in previous releases on the same platform [assuming the same build options]. What’s New In Python 3.0 — Python 3.8.4 documentation
In Python3, sys.maxint
has been removed, and sys.maxsize
has been added.
- sys.maxsize — System-specific parameters and functions — Python 3.8.4 documentation
sys.maxsize
is 2**31-1
on a 32-bit environment and 2**63-1
on a 64-bit environment, like sys.maxint
in Python2.
import sys
print[sys.maxsize]
# 9223372036854775807
print[type[sys.maxsize]]
#
print[sys.maxsize == 2**63 - 1]
# True
Converted to binary and hexadecimal numbers with bin[]
and hex[]
, sys.maxsize
is expressed as follows.
- Convert binary, octal, decimal, and hexadecimal in Python
print[bin[sys.maxsize]]
# 0b111111111111111111111111111111111111111111111111111111111111111
print[hex[sys.maxsize]]
# 0x7fffffffffffffff
sys.maxsize
is not the max value of int
, and you can handle larger values as memory is available.
i = 10**100
print[i]
# 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
print[i > sys.maxsize]
# True
The floating-point number float
has inf
representing infinity. inf
is judged to be larger than any value of int
.
print[float['inf']]
# inf
print[i > float['inf']]
# False
See the following article about infinity inf
.
- "inf" for infinity in Python