Bug or intended behavior?

[Chris Angelico]

On Wed, Jun 7, 2017 at 2:44 AM, Peter Pearson <pkpearson at nowhere.invalid> wrote:
> On Tue, 6 Jun 2017 03:10:05 +1000, Chris Angelico wrote:
>> On Tue, Jun 6, 2017 at 3:01 AM, Peter Pearson wrote:
> [snip]
>>> Say
>>>     "foo %s" % (1-2)
>>> not
>>>     ("foo %s" % 1) - 2
>>> .
>>>
>>> Personally I prefer a less compact but more explicit alternative:
>>>
>>>     "foo {}".format(1-2)
>>
>> The trouble with the zen of Python is that people now use the word
>> "explicit" to mean "code that I like". What is more explicit here? It
>> uses a method call instead of an operator, but either way, it's
>> completely explicit that you want to populate the placeholders in a
>> template string.
>
> I meant simply that when you call "format", you don't have to think
> about the precedence of the "%" operator.  Maybe "explicit" isn't
> the right word; I just make fewer mistakes when I stick with things
> that I use all the time (function calls, in this case).

Thank you, that's a more accurate way to describe it. If you don't
want to memorize precedence but like the simplicity of percent
formatting, try this:

def fmt(str, args):
    return str % args

fmt("foo %s", 1-2)

Also avoids the problem of formatting a tuple the wrong way by mistake.

ChrisA