How to find cube root using Python

Question

Here is how  this is the best way  I have found   x   int raw input  Enter an integer      for ans in range 0  abs x    1       if ans    3    abs x           break if ans    3    abs x       print x   is not a perfect cube   else      if x  lt  0          ans   -ans     print  Cube root of     str x      is     str ans    Is there a better way  preferably one that avoids having to iterate over candidate values

User · Answer

def cube x       if 0 lt  x  return x   1  3       return - -x    1  3   print  cube 8   print  cube -8     Here is the full answer for both negative and positive numbers    gt  gt  gt   2 0 -2 0  gt  gt  gt     Or here is a one-liner   root cube   lambda x  x   1  3   if 0 lt  x else - -x    1  3

User · Answer

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

User · Answer

The best way is to use simple math    gt  gt  gt  a   8  gt  gt  gt  a   1  3   2 0   EDIT  For Negative numbers    gt  gt  gt  a   -8  gt  gt  gt  - -a    1  3   -2 0   Complete Program for all the requirements as specified  x   int input  Enter an integer      if x gt 0      ans   x   1  3       if ans    3    abs x           print x   is not a perfect cube   else      ans   -  -x    1  3        if ans    3    -abs x           print x   is not a perfect cube    print  Cube root of     str x      is     str ans

[python] How to find cube root using Python?

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