Optimizing Inner Loop Copy

[Mark E. Fenner]

John Machin wrote:

> 
> Mark E. Fenner wrote:
> 
>> Here's my class of the objects being copied:
> 
> Here's a couple of things that might help speed up your __init__
> method, and hence your copy method:
> 
>>
>> class Rule(list):
>>     def __init__(self, lhs=None, rhs=None, nClasses=0, nCases=0):
> 
>     def __init__(self, lhs=None, rhs=(), nClasses=0, nCases=0):
> 
>>         self.nClasses = nClasses
>>         self.nCases = nCases
>>
>>         if lhs is not None:
>>             self.extend(lhs)
> what does the extend method do? If it is small, perhaps inline a copy
> of its code here.
>>
>>         if rhs is None:
>>             self.rhs=tuple()
>>         else:
>>             self.rhs=rhs
> 
> Replace the above 4 lines by:
>     self.rhs = rhs
>  
> HTH,
> John

John,

Thanks.  I thought of those at the same you did!  I also incorporated one
other use of the default=() + no conditional:

class Rule(list):
    def __init__(self, lhs=(), rhs=(), nClasses=0, nCases=0):
        self.nClasses = nClasses
        self.nCases = nCases
        self.extend(lhs) # note, self is a list so this is list.extend
        self.rhs=rhs

    def copy(self):
        return Rule(self,
                    self.rhs,
                    self.nClasses,
                    self.nCases)