En Tue, 24 Jul 2007 19:51:30 -0300, Boris Dušek <[EMAIL PROTECTED]> escribió:
> in Java, when I want to pass input to a function, I pass > "InputStream", which is a base class of any input stream. > > In Python, I found that "file" objects exist. While specifying > argument types in Python is not possible as in Java, it is possible to > check whether an object is an instance of some class and that's what I > need - I need to check if an argument is a "file"-like object, and if > yes, behave accordingly, if not, treat the argument as string with > URL. No, it's not what you need, it's what you *think* you need :) > P.S.: The code should finally look in esence something like this: Posting this is much better that saying what you think you need. > if isinstance(f, file): > pass > elif isinstance(f, string): > f = urllib.urlopen(f) > else: > raise "..." > process_stream(f) I can imagine that process_stream is something like this: def process_stream(f): ... data = f.read() ... or similar. Then, you dont need a file object: you need something with a read() method. So, this is what you should check in your code above. if hasattr(f, "read"): pass elif isinstance(f, basestring): f = urllib.urlopen(f) else: raise TypeError, "Expecting either a readable file-like object or an URL" process_stream(f) Or perhaps: if isinstance(f, basestring): f = urllib.urlopen(f) process_stream(f) and just let the exception happen below at f.read - which explains itself rather well. -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
