Warnings can be helpful when developing, especially if your code will be heavily reused. Here are some examples, but for official documentation on python warnings visit: https://docs.python.org/3.8/library/warnings.html

The default type of a python warning is a UserWarning.



In [1]:

    
import warnings

def add_int(x,y):
    
    if not isinstance(x,int):
        warnings.warn('The x variable type needs to be an int, instead type '+str(type(x))+' was passed')
        return None
    
    elif not isinstance(y,int):
        warnings.warn('The y variable type needs to be an int, instead type '+str(type(x))+' was passed')
        return None
        
        z=x+y
        
    return z

add_int(2,3.0)









    



C:\Users\15037\Anaconda3\lib\site-packages\ipykernel_launcher.py:10: UserWarning: The y variable type needs to be an int, instead type <class 'int'> was passed
  # Remove the CWD from sys.path while we load stuff.

You can call other warning types, such as a DeprecationWarning.



In [2]:

    
class BasicMath:
    
    def add_int(self,x,y):
    
        warnings.warn('The add_int function will be deprecated in a future release, please use the add function.',DeprecationWarning)

        if not isinstance(x,int):
            warnings.warn('The x variable type needs to be an int, instead type '+str(type(x))+' was passed')
            return None

        elif not isinstance(y,int):
            warnings.warn('The y variable type needs to be an int, instead type '+str(type(x))+' was passed')
            return None

            z=x+y

        return z

    def add(self,x,y):
        return(x+y)
    
BasicMath().add_int(2,3.0)









    



C:\Users\15037\Anaconda3\lib\site-packages\ipykernel_launcher.py:5: DeprecationWarning: The add_int function will be deprecated in a future release, please use the add function.
  """
C:\Users\15037\Anaconda3\lib\site-packages\ipykernel_launcher.py:12: UserWarning: The y variable type needs to be an int, instead type <class 'int'> was passed
  if sys.path[0] == '':

You can choose whether you want to filter out warnings.



In [3]:

    
import sys

if not sys.warnoptions:
    import warnings
    warnings.simplefilter("ignore")

print(BasicMath().add_int(2,3.0))









    



None

You can also choose to throw warnings as errors.



In [4]:

    
if not sys.warnoptions:
    import warnings
    warnings.simplefilter("error")

print(BasicMath().add_int(2,3.0))









    



---------------------------------------------------------------------------
DeprecationWarning                        Traceback (most recent call last)
<ipython-input-4-9724e90aae33> in <module>
      3     warnings.simplefilter("error")
      4 
----> 5 print(BasicMath().add_int(2,3.0))

<ipython-input-2-21136eb78d70> in add_int(self, x, y)
      3     def add_int(self,x,y):
      4 
----> 5         warnings.warn('The add_int function will be deprecated in a future release, please use the add function.',DeprecationWarning)
      6 
      7         if not isinstance(x,int):

DeprecationWarning: The add_int function will be deprecated in a future release, please use the add function.



In [ ]: