how to build arbitrarily-sized lists in one fell swoop?

[Remco Gerlich]

Samuel Scarano wrote in comp.lang.python:
> There's a simple thing I want to do in python but I can't find a way that is
> obvious to the reader and efficient for the interpreter. I want to make a
> list with n copies of x.
> 
> This is the way that's most obvious to me:
> 
> l = []
> for i in range(n):
> 	l.append(x)
> 
> But that looks awfully verbose for Python, and I'm sure there's a more
> efficient way.
> 
> Then there's:
> 
> l = map(lambda y: x, range(n))
> 
> That's briefer, but it still involves a lot of function calls, and the
> wasteful construction of a range.
> 
> So what's the right way?

l = [x]*n

Does what you do here. I don't know what kind of object x is, but note
that this doesn't make *copies* of x; if it's some instance, then all
elements of l will be a reference to the same old x. Same for your
methods.

-- 
Remco Gerlich,  scarblac at pino.selwerd.nl
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