On Wed, 04 Aug 2010 12:58:18 -0700, Eric J. Van der Velden wrote:
> Hello,
>
> Suppose
>
> class C:
> def __init__(self,name):self.name=name
>
> I was wondering if I could make the __init__ a lambda function,
Of course you can. Lambdas aren't special types of functions, they are
*syntax* for creating a function consisting of a single expression, and
your __init__ function is a single expression.
These two are almost identical:
def spam(a, b):
return a+b
spam = lambda a, b: a+b
The only(?) differences are spam.func_name or spam.__name__.
> but
>
> class C:
> __init__=lambda self,self.name:None
>
> and then later,
>
> C('Hello')
>
> does not work; the first argument, self, is assigned all rigth, but you
> cannot write the second argument with a dot, self.name .
That gives a syntax error no matter whether you use it in a lambda form
or an ordinary function:
>>> def f(self,self.name):
File "<stdin>", line 1
def f(self,self.name):
^
SyntaxError: invalid syntax
So the problem has nothing to do with lambda. What you want is:
lambda self: self.name = None
but of course that doesn't work either, because self.name = None is not
an expression, it's a statement. So:
class C:
__init__ = lambda self: setattr(self, 'name', None)
But don't do this. Seriously. Just because it is syntactically valid and
does what you want, doesn't mean you should do it. Unless you have really
good reason, and saving a single line of source code is a *bad* reason,
just stick to the standard idiom that everyone can read without going
"WTF is this guy doing this for???".
class C:
def __init__(self):
self.name = None
--
Steven
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