Python math library | isclose() method

• Last Updated : 22 May, 2019

In Python math module, math.isclose() method is used to determine whether two floating point numbers are close in value. For using this function you must import math module.

Syntax: isclose(a, b, rel_tol = 1e-09, abs_tol 0.0)

Parameters:
rel_tol: maximum difference for being considered “close”, relative to the magnitude of the input values
abs_tol: maximum difference for being considered “close”, regardless of the magnitude of the input values

-> rel_tol and abs_tol can be changed by using keyword argument, or by simply providing directly as according to their positions in the parameter list.

Return Value : Return True if a is close in value to b, and False otherwise.

Note: For the values to be considered close, the difference between them must be smaller than at least one of the tolerances.

Code #1:

 # Importing Math moduleimport math  # printing whether two values are close or notprint(math.isclose(2.005, 2.005))print(math.isclose(2.005, 2.004))print(math.isclose(2.006, 2.005))

Output:

True
False
False

Code #2:

 # Importing Math moduleimport math  # printing whether two values are close or notprint(math.isclose(2.005, 2.125, abs_tol = 0.25))print(math.isclose(2.547, 2.0048, abs_tol = 0.5))print(math.isclose(2.0214, 2.00214, abs_tol = 0.02))

Output:

True
False
True

You can change absolute tolerance, as in above case absolute tolerance is different in all three cases.

Reference: Python math library

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