[Python-ideas] Python Users Aren't Perfect

Ned Batchelder ned at nedbatchelder.com
Mon Dec 12 14:26:16 CET 2011

On 12/12/2011 8:19 AM, Antoine Pitrou wrote:
> Le lundi 12 décembre 2011 à 08:15 -0500, Ned Batchelder a écrit :
>> Believe me, I understand the issues.  It is true, though that the
>> single-element tuple syntax is often a surprise to people, and often
>> well into their Python learning experience.  We often repeat, "it isn't
>> parens that make a tuple, but a comma."  Then why when displaying a
>> tuple does Python insist on using parens around it?
>>   >>>  1, 2, 3
>>       (1, 2, 3)
> I would say:
> - because it's easier to read (subjectively so, I guess)
> - because it's easier to copy/paste into an expression without running
> into precedence problems
Yes, those are good reasons.  And you can see why Python's insistence on 
showing tuples with parens contributes to the gotcha that the parens are 
a red herring, and it's the commas that are important.  Also, who hasn't 
said this to a beginner:  "lists and tuples are very similar, lists use 
square brackets, tuples use parens"?  Somehow, in a list, the commas 
don't make a tuple...  It's complicated.

I welcome Richard's help in explaining this issue to beginners.

> Regards
> Antoine.
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