python-dev summary, July 16-31

[Thomas Bellman]

pinard at iro.umontreal.ca (François Pinard) wrote:

> There is one case, however, where using parentheses with tuples is worth
> doing, and this is for long lists of tuple elements spanning more than one
> line.  Parentheses combined with proper indenting help the eye at catching
> the overall structure.  For short tuples that fit on a line, parentheses are
> overkill to me.

There are a couple of other occasions where you *should* use
parentheses, or you won't get what you want:

* When the tuple is an argument to a function call.
  foo(1,2,3) and foo((1,2,3)) are very different things.
* When the tuple is an element in a list or another tuple.
  [1,2,3,4,5,6] and [1,(2,3),(4,5),6] are very different.
* When the tuple is a key or a value in a dictionary:
  { (1,2):"one and two", "three and four":(3,4) } works, while
  { 1,2:"one and two", "three and four":3,4 } doesn't.


>     for x in 1, 2, 3:
>         pass

I would always write this as

    for x in [ 1, 2, 3 ]:
	pass

Hmm, actually, on closer consideration, I think I would write
it as

    x = 3

:-)


-- 
Thomas Bellman,   Lysator Computer Club,   Linköping University,  Sweden
"God is real, but Jesus is an integer."      !  bellman @ lysator.liu.se
                                             !  Make Love -- Nicht Wahr!