Re: Multiple constructors

[vincent wehren]

Philip Smith wrote:
Call this a C++ programmers hang-up if you like.
I don't seem to be able to define multiple versions of __init__ in my matrix 
class (ie to initialise either from a list of values or from 2 dimensions 
(rows/columns)).

Even if Python couldn't resolve the __init__ to use on the basis of argument 
types surely it could do so on the basis of argument numbers???

At any rate - any suggestions how I code this????
Checking the number of arguments ain't all that hard:
class Klass:
   def __init__(*args):
       self.args = args
       if len(self.args) == 1:
           # etc.
This feels rather unpythonic, though. Maybe you could use factory 
functions, forgetting about  __init__ all together (2.2 or higher):

class Klass(object):
    def fromList(seq):
        result = Klass()
        # populate attributes here
        # and return the requested object
        return result
    fromList = staticmethod(fromList)
    def fromDimensions(cols, rows):
        result = Klass()
        # populate attributes here
        # and return the requested object
        return result
   fromDimensions = staticmethod(fromDimensions)
   #more methods  here
k = Klass.fromList(seq)
etc..
Regards
--
Vincent Wehren



Thanks
Phil 


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