scipy.constants.pi is simply a plain float, the same value as math.pi and numpy.pi, included in SciPy's constants module purely for convenience so code that's already importing other physical/mathematical constants from scipy.constants doesn't also need a separate import from the math module just for pi. It's accurate to the full precision of a Python float, roughly 15-17 significant decimal digits.
1Understanding constants.pi
scipy.constants.pi is simply a plain float, the same value as math.pi and numpy.pi, included in SciPy's constants module purely for convenience so code that's already importing other physical/mathematical constants from scipy.constants doesn't also need a separate import from the math module just for pi. It's accurate to the full precision of a Python float, roughly 15-17 significant decimal digits.
scipy.constants.pi, math.pi, and numpy.pi are all exactly the same floating-point value — use whichever one is already imported/available in your code rather than adding an extra import just to get pi from a different module.
from scipy import constants
radius = 5
area = constants.pi * radius ** 2
print(area)2Practical Example
Here is a real-world application of constants.pi showing how it is used in production SciPy code.
from scipy import constants
import math
print(constants.pi == math.pi)3Best Practices
Follow these guidelines when working with constants.pi:
1. Use whichever pi you already have imported, scipy, math, or numpy, rather than adding a redundant extra import for the same value
2. Reach for scipy.constants specifically when you also need other physical constants alongside pi, to keep imports consolidated
3. Never hardcode a truncated decimal approximation of pi, like 3.14, in code — use the full-precision constant instead
Tip: scipy.constants.pi, math.pi, and numpy.pi are all exactly the same floating-point value — use whichever one is already imported/available in your code rather than adding an extra import just to get pi from a different module.
from scipy import constants
radius = 5
area = constants.pi * radius ** 2
print(area)