2009/9/3 Albert-Jan Roskam <fo...@yahoo.com>:
> Hi,
>
> I'm wondering what is the most common method of input validation. See the
> example below.
> -Is the code below the most common/recognizable way something like this is
> done?
> -Which of the options #1 and #2 is the preferred method? Option #2 looks less
> esoteric, but #1 seems better when you have to check for several data types
> simultaneously.
>
> Thanks!
> Albert-Jan
>
> import os.path, textwrap
>
> def main(param):
> if validate_input(param) == "LT":
> return param[-1]
> elif validate_input(param) == "FILE":
> f = open(param, "rb").readlines()
> return " ".join(f)
> elif validate_input(param) == "STR":
> return textwrap.wrap(param)
> else:
> print "Invalid input!"
> return None
>
> def validate_input (param):
> if param.__class__ in (list, tuple): #option 1
> return "LT"
> elif isinstance(param, str): # option 2
> if os.path.isfile(param):
> return "FILE"
> else:
> return "STR"
> else:
> return None
>
> print main(param=[1,2,3])
> print main(param="d:/temp/txt.txt")
> print main(param="yeah but yeah, but no")
> print main(param=1.0)
>
>
>
>
>
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>
isinstance can take a tuple of types:
def validate_input (param):
if isinstance(param, (list, tuple)): #option 1
return "LT"
elif isinstance(param, str): # option 2
if os.path.isfile(param):
return "FILE"
else:
return "STR"
else:
return None
Also, file-type objects aren't instances of str...
--
Rich "Roadie Rich" Lovely
There are 10 types of people in the world: those who know binary,
those who do not, and those who are off by one.
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