2016-12-12 17:29 GMT+01:00 Bryon Adams <bryonad...@openmailbox.org>:
> Is there a way to force my argument to always be a string before entering
> the function? Else, is there a better way to go about this? In whatever
> program I write, I could change what I want as input to be a string prior
> to tossing it into the function but I think it would make more sense for my
> function to already do it. The function otherwise works. This is on
> Python3.5 under Fedora 25
>
> The only other thing I could think of would be to put exceptions in for
> syntax error and whatever else pops up as I go along, though to be honest
> it *should* always be a string that gets dumped into the function. Not sure
> how I'd put the exception together though since it's not making it into the
> function prior to failing.
>
> -------------------------------------------
> Error from interpreter: (looks like it's taking issue with it being a
> number it doesn't know how to deal with)
>
> >>> ip_checker(169.254.0.1)
> File "<stdin>", line 1
> ip_checker(169.254.0.1)
> ^
> SyntaxError: invalid syntax
>
> -------------------------------------------
> My function:
>
> def ip_checker(ip_address):
> '''
> Takes one IP address and checks whether it is valid or not.
> '''
> # Try to convert to integers
> try:
> ip_addr = [int(i) for i in ip_address.split('.')]
> except ValueError:
> print('Invalid characters were entered or an octet is empty, please
> try again.')
> return False
>
> # Determine how many octets were entered
> if len(ip_addr) != 4:
> print('Incorrect number of octets, please try again.')
> return False
>
> # Determine validity of first octet
> if ((ip_addr[0] > 223) and (ip_addr[0] < 256)) or (ip_addr[0] == 0):
> print('First octet is reserved or zero.')
> return False
>
> # Determine if this is a loopback address
> if ip_addr[0] == 127:
> print('I think that was a loopback address, please try again.')
> return False
>
> # Determine if this is an APIPA address
> if (ip_addr[0] == 169) and (ip_addr[1] == 254):
> print('I think that was an APIPA address, please try again.')
> return False
>
> # Determine if the last three octets are between 0-255
> for octet in (ip_addr[1], ip_addr[2], ip_addr[3]):
> if octet not in [i for i in range(0,256)]:
> print('Octet too large or too small, please try again.')
> return False
> else:
> print('The IP address {} is valid.'.format(ip_address))
> return True
>
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Hi Btryon,
to to force to process a string is convert the function argument to string:
def ip_checker(ip_address):
'''
Takes one IP address and checks whether it is valid or not.
'''
ip_address = str(ip_address)
And after this you can process it as a string.
To write more readable and more beautiful code, You can put all your
checkings into small functions inside the ip_checker function:
def ip_checker(ip_address):
def determine_validity_of_first_octet():
....
def determine_if_this_is_a_loopback():
...
determine_validity_of_first_octet()
determine ...
and so on
:-)
BR.
George
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