Anonymus functions revisited
onurb at xiludom.gro
Tue Mar 22 11:12:35 CET 2005
Claudio Grondi wrote:
> For me, one of the reasons for using Python
> is the ease and the intuivity of reading its
I guess this is true for many of us. Now 'ease and intuitivity' stronly
depends on one's background...
> I have a problem with intuitively getting
> what is going on when using a pattern like
> (x,y,z=0) -> (x,y,z)
> where I expect at the first glance some
> C code with access to class members.
There are nothing like a class or a class member in C.
> At least I must start looking at the code
> more closely thinking why is someone
> using such a construct.
> lambda x,y,z=0:(x,y,z)
> is a problem for me.
Not for me. It's clearly a function that takes 2 mandatory and one
optional argument (which default to 0), and returns a tuple of it's
it's named equivalent is:
def make_three_tuple(x, y, z=0):
return (x, y, z)
> Why not:
> except NameError:
Because it does not do the same thing ?-)
Because, if it did, it would still require 5 times more lines of code to
do the same thing (hence it's more error-prone by a factor a 5) ?
Because it uses an exception, which is far less efficient than using a
default argument ?
Because the name error could be on x and/or y too, and the try:except
clause would hide it ?
I stop here, but I think I could think of more good (IMHO) reason to
prefer the lambda form.
> Watching the last piece of code
> can even directly be seen, that there
> is eventually a NameError
> problem with z to handle,
No. AFAICT, the name error could be with x and/or y and/or z.
> so where is the gain of using
> lambda or the mapping?
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb at xiludom.gro'.split('@')])"
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