creating lists question?

[Steve]

Gandalf wrote:

> The * operator applied to a tuple will create another tuple consisting 
> of the same objects but many times. For example,
> (2,3,) *3 
> will create (2,3,2,3,2,3)
> 
> However, if you do this:
> 
> (obj,)*3
> 
> then you will get
> 
> (obj,obj,obj,)
> 
> You will get references to the the same object.  :-)

Which leads me to this nifty method:

a,b,c,d = map(lambda L: L[:], [[]]*4)

Or as a list comprehension:

a,b,c,d = [L[:] for L in [[]]*4]

It works, but it is moderately cryptic and relies on 
the programmer knowing the names of all the variables 
at write-time.

-- 
Steven D'Aprano