Thoughts on using isinstance

abcd codecraig at
Wed Jan 24 13:38:30 CET 2007

In my code I am debating whether or not to validate the types of data
being passed to my functions.  For example

def sayHello(self, name):
    if not name:
        rasie "name can't be null"
    if not isinstance(name, str):
        raise "name must be a string"
    print "Hello " + name

Is the use of isinstance a "bad" way of doing things?  is it a "heavy"
operation?  for example, if I use this in each function validate input
will it slow things down a lot?

just curious how you might handle this type of situation (other than
not validating at all).


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