Value for epsilon in Python

python comparison floating-point epsilon
thornate picture thornate · Mar 2, 2012 · Viewed 74.2k times · Source

Is there a standard value for (or method for obtaining) epsilon in Python? I need to compare floating point values and want to compare against the smallest possible difference.

In C++ there's a function provided numeric_limits::epsilon( ) which gives the epsilon value for any given data type. Is there an equivalent in Python?

Answer

strcat picture strcat · Mar 2, 2012

The information is available in sys.float_info, which corresponds to float.h in C99.

>>> import sys
>>> sys.float_info.epsilon
2.220446049250313e-16

Related questions

Why does comparing strings using either '==' or 'is' sometimes produce a different result?

I've got a Python program where two variables are set to the value 'public'. In a conditional expression I have the comparison var1 is var2 which fails, but if I change it to var1 == var2 it returns True. Now if …

Read More
String comparison in Python: is vs. ==

I noticed a Python script I was writing was acting squirrelly, and traced it to an infinite loop, where the loop condition was while line is not ''. Running through it in the debugger, it turned out that line was …

Read More
How do I do a case-insensitive string comparison?

How can I do case insensitive string comparison in Python? I would like to encapsulate comparison of a regular strings to a repository string using in a very simple and Pythonic way. I also would like to have ability to …

Read More