How to find cube root using Python? [duplicate]

by

You could use x ** (1. / 3) to compute the (floating-point) cube root of x.

The slight subtlety here is that this works differently for negative numbers in Python 2 and 3. The following code, however, handles that:

def is_perfect_cube(x):
    x = abs(x)
    return int(round(x ** (1. / 3))) ** 3 == x

print(is_perfect_cube(63))
print(is_perfect_cube(64))
print(is_perfect_cube(65))
print(is_perfect_cube(-63))
print(is_perfect_cube(-64))
print(is_perfect_cube(-65))
print(is_perfect_cube(2146689000)) # no other currently posted solution
                                   # handles this correctly

This takes the cube root of x, rounds it to the nearest integer, raises to the third power, and finally checks whether the result equals x.

The reason to take the absolute value is to make the code work correctly for negative numbers across Python versions (Python 2 and 3 treat raising negative numbers to fractional powers differently).

More Related Contents:

  1. code that count the amount of yes and no in a list [closed]
  2. how to unpack a tuple in this form (‘abc’, [20, 20])? [closed]
  3. How to pass arguments to a Button command in Tkinter?
  4. Django MEDIA_URL and MEDIA_ROOT
  5. TypeError: a bytes-like object is required, not ‘str’
  6. Relative imports – ModuleNotFoundError: No module named x
  7. pandas: merge (join) two data frames on multiple columns
  8. Pandas Extract Number from String
  9. How to use asyncio with existing blocking library?
  10. tkinter.TclError: image “pyimage3” doesn’t exist
  11. Simplest async/await example possible in Python
  12. ValueError: malformed string when using ast.literal_eval
  13. How do I upgrade the Python installation in Windows 10?
  14. Convert float to string in positional format (without scientific notation and false precision)
  15. Object of type ‘map’ has no len() in Python 3
  16. What is the purpose of Python’s itertools.repeat?
  17. Prime factorization – list
  18. Calling a Python function with *args,**kwargs and optional / default arguments
  19. Alternative to execfile in Python 3? [duplicate]
  20. What encoding does open() use by default?
  21. Given a path, how can I extract just the containing folder name?
  22. How to extend Python Enum?
  23. Python pandas: how to remove nan and -inf values
  24. What should I put in the body of an abstract method?
  25. Python 3.4: How to import a module given the full path? [duplicate]
  26. How to change all the dictionary keys in a for loop with d.items()?
  27. Anaconda unicode error on command line startup on Windows
  28. bash: Python import – Command not found for pandas
  29. Issue with regex backreference in Python
  30. What difference between pickle and _pickle in python 3?

Leave a Comment