Constructor class problem

Joal Heagney joal at bigpond.net.au
Tue Mar 22 12:38:55 CET 2005


Diez B. Roggisch wrote:
> Wolfgang wrote:
> 
> 
>>Hi,
>>I am a newbie and have to modify some python moduls.
>>I get the followin error:
>>TypeError: __init__() takes exactly 3 arguments (2 given)
>>
>>Here the code snippet:
>>class gXconv:
>>    def __init__(self, pathValue):
>>        self.pathValue=pathValue
>>        self.__sections = {}
>>        self.__spalten = {}
>>        self.labelfiles=[]
>>etc.....
>>
>>call:
>>    try:
>>        gx=gXconv.gXconv(gXconfPath)
>>    except gXconv.gXconvertError, msg:
>>        print msg
>>        sys.exit(1)
> 
> 
> 
> That error can't appear in the above code - is the line in the stacktrace
> amongst the shown ones? I doubt it. 
> 
> The error means that you tried to call a function with less arguments than
> it expected. As in __init__ the first argument is implicit on creation of
> an object, the above errormessage indicates that there is an __init__
> of the form
> 
> class Foo:
>     def __init__(self, arg1, arg2)
>        pass
> 
> called like this
> 
> Foo("bar")
> 
> But as the only constructor you show _has_ only one additional argument
> besides self and line 
> 
> gx=gXconv.gXconv(gXconfPath)
> 
> shows that you called it properly, the error must come from somewhere else.
> 

And the easiest way to track it down is to add some temporary
print "I am in <some function or method name>."
debug messages through your code.
By looking at which messages pop up, you can trace what happens just 
before your program bombs.

Joal



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