[docs] [issue23153] Clarify Boolean Clause Results

Ethan Furman report at bugs.python.org
Sat Jan 3 19:57:26 CET 2015

Ethan Furman added the comment:

Apologies, my wording was poor -- the last item evaluated is the one returned, but all items may not be evaluated.  As soon as the answer is known Python stops evaluating any remaining items.

So in the example:

  --> string1, string2, string3 = '', 'Trondheim', 'Hammer Dance'
  --> string1 or string2 or string3

string2 is returned because it satifies the `or` conditions, and string3 is not evaluated.

Re: John

I appreciate you have many years of programming experience, but there are going to be differences between what is good practice in those languages and what is good practice in Python.  IMO, the big three differences are:

  - white space indentation
  - everything is an object (variables, functions, classes, instances,
    any piece of data...)
  - everything has a truthy of falsey value -- e.g.

    --> string1, string2, string3 = '', 'Trondheim', 'Hammer Dance'
    --> if string2:
    ...    print('string2 has a value!  It is %s' % string2)
    'string2 has a value!  It is Trondheim'

    notice there is no `if bool(string2)` or `if string2 == False` (which would be False).

As far as finding that bit of the tutorial confusing, there is no way to have a single document that is crystal clear to everyone who reads it.  This section is correct, as is section 4.1 -- `or` is being used, so the operand is returned, not True or False.


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