The maximum integer in Python 2 is available by calling sys.maxint.
What is the maximum float or long in Python?
See also: Maximum and Minimum values for ints.
4 Answers
For float have a look at sys.float_info:
>>> import sys >>> sys.float_info sys.float_info(max=1.7976931348623157e+308, max_exp=1024, max_10_exp=308, min=2.2250738585072014e-308, min_exp=-1021, min_10_exp=-307, dig=15, mant_dig=53, epsilon=2.220446049250313e-16, radix=2, rounds=1) Specifically, sys.float_info.max:
>>> sys.float_info.max 1.7976931348623157e+308 If that's not big enough, there's always positive infinity:
>>> infinity = float("inf") >>> infinity inf >>> infinity / 10000 inf int has unlimited precision, so it's only limited by available memory.
5 Comments
ladyfafa
actually, I found the sys.maxint is quite enough to my application
Aleksei Fedotov
It seems
sys.float_info is available starting from v2.6. How about v2.3-5?
Bob Stein
Note sys.float_info.min is defined as "minimum positive normalized float". Smaller denormal values are possible, down to
5e-324
Dima Tisnek
Cool, both are very useful.
inf for all things python, and float_info.max as a workaround when the earlier doesn't work, for example time.sleep(float("inf")) is not allowed :(
Joachim Wagner
@ladyfafa: sys.maxint is gone in Python 3, see also comments in the other answer and stackoverflow.com/questions/13795758/…
sys.maxsize (previously sys.maxint) is not the largest integer supported by python. It's the largest integer supported by python's regular integer type.
5 Comments
Katriel
+1 This is important. In Py3k, it's nearly meaningless -- it's the point at which Python (transparently!) changes the underlying datatype to
long.
Scott Griffiths
@katrielalex:
sys.maxint isn't even defined in Python 3, it's called sys.maxsize, which is probably to be preferred in Python 2 as well.
Mark Dickinson
@Scott Griffiths: Not quite.
sys.maxsize (introduced in Python 2.6) and sys.maxint are two different things. The first gives the maximum number of objects allowed in a collection (e.g., maximum size of a list, dict, etc.), and corresponds to a signed version of the C size_t type; the second is the point after which the int type switches to long, and is the max value of a C long. On some platforms the two values are different: e.g., on 64-bit Windows, sys.maxsize is 2**63-1 and sys.maxint is 2**31-1.Scott Griffiths
@Mark Dickinson: Thanks for the correction - I hadn't realised they could ever be different (with 64-bit Python on Snow Leopard they are both
2**63-1).
If you are using numpy, you can use dtype 'float128' and get a max float of 10e+4931
>>> np.finfo(np.float128) finfo(resolution=1e-18, min=-1.18973149536e+4932, max=1.18973149536e+4932, dtype=float128) 
Comments
In python 3 there is no sys.maxint There is a sys.maxsize
>>> sys.maxsize 2147483647 That does not mean that the maximum int is limited to 2 billion! It means that the size of the object containing the integer has a maximum size of 2 billion bytes. I.e. a very very large number
For float have a look at sys.float_info
>>> sys.float_info sys.float_info(max=1.7976931348623157e+308, max_exp=1024, max_10_exp=308, min=2.2250738585072014e-308, min_exp=-1021, min_10_exp=-307, dig=15, mant_dig=53, epsilon=2.220446049250313e-16, radix=2, rounds=1) And specifically sys.float_info.max
>>> sys.float_info.max 1.7976931348623157e+308 3 Comments
Max
sys.maxsize gives me 9223372036854775807 ...
Holger Bille
I do too. We are on 64 bits now :-)
Max
Congrats! but... "now"? it was time! I think I had 64 bits already back in 2022... Not you?
sys.maxintin Python 3.