list comprehension question

Roel Schroeven rschroev_nospam_ml at
Wed May 6 11:26:25 CEST 2009

John Yeung schreef:
> Essentially, if you see [B A] over and over and over again, when
> finally confronted with LCs of more "elements", it's not immediately
> clear that the pattern of increasing nestedness is
>   [B A] => [C A B] => [D A B C] => etc.
> rather than
>   [B A] => [C B A] => [D C B A] => etc.
> Maybe we're wired wrong, but there are many of us who find the second
> pattern more logical, which is why it is so easy for us to mess up the
> order of the nesting in a more complex LC.

Indeed, that is exactly the reason why I find it difficult to read
nested loop comprehensions, and why I almost never use them.

The saddest aspect of life right now is that science gathers knowledge
faster than society gathers wisdom.
  -- Isaac Asimov

Roel Schroeven

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