Static Methods & Static Variables

Class Sum:

<code># static variable
num_of_sum_ops = 0

@staticmethod
def getSum(*args):
    sum = 0
    for i in args:
        sum += int(i)
    Sum.num_of_sum_ops += 1
return sum
</code>

Note: * static variables are assigned in class but not in init * static methods have @staticmethod keyword.

<code>* static methods/variables are shared like Global functions and variables
</code>

Exception Handling

When an Error Occurs
When something out of ordinary like close a file

try: aList = [1, 2, 3] print(aList[3]) except IndexError: print(‘yep, we had index error’)

except KeyError: print(‘ ooh, we had KeyError’)

except: print(‘ oh yea, you are screwed, we don’t what caused it’)

Custom Exception

kwargs -> keyword args

Defining Custom exception

<code>class DogNameError(Excepton):

    def __init__(self, *args, **kwargs):
        Exception.__init__(self, *args, **kwargs)
</code>

Example

<code>try:
    dogName = input(“what is your dog name:”)
    if any(char.isdigit() for char in dogName):
        raise DogNameError ## our custom Error fns
except: DogNameError:
    print(“cool man, you got your exception”)

else:
    # if exception does not occur
    print(“no errors occured”)
finally:
    # does not matter if excetion happened
    print(“Inputs are ….”)
</code>

Note:

kwargs mean keyword arguments
created a custom exception(class)
custom exception class is supposed to be a inheritance of Exception class
we used keyword raise to raise exception
use else for cases like if read a file then print you were able to read. and the content in it.
- use finally key word to do actions which much happened like closing a file and so

try: myFile = open(“helloworld”, encoding=“utf-8”)

except FileNotFoundError as ex: print(“that file was not found”) print(ex.args)

else: print(“File:“, myFile.read()) myFile.close() finally: print(“tried working with file”)

Note:

we are catching error as ex using key word as

Source: Static methods, Exceptions