Does anyone else use this little idiom?

Nick Craig-Wood nick at craig-wood.com
Tue Feb 5 16:30:05 CET 2008


miller.paul.w at gmail.com <miller.paul.w at gmail.com> wrote:
>  Ruby has a neat little convenience when writing loops where you don't
>  care about the loop index: you just do n.times do { ... some
>  code ... } where n is an integer representing how many times you want
>  to execute "some code."
> 
>  In Python, the direct translation of this is a for loop.  When the
>  index doesn't matter to me, I tend to write it as:
> 
>  for _ in xrange (1,n):
>     some code
> 
>  An alternative way of indicating that you don't care about the loop
>  index would be
> 
>  for dummy in xrange (1,n):
>     some code

I use pychecker a lot.  It views variables called [ '_', 'unused',
'empty', 'dummy' ] as names to ignore if they haven't been used.

So according to pychecker '_' and 'dummy' would both be OK.

As for me personally, I usually use '_' but sometimes use 'dummy'
depending on the surrounding code.

Note that this idiom is fairly common in python too

 wanted, _, _, _, also_wanted = a_list

which looks quite neat to my eyes.

-- 
Nick Craig-Wood <nick at craig-wood.com> -- http://www.craig-wood.com/nick



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