[Python-Dev] Formatting mini-language suggestion

[James Y Knight]

On Mar 11, 2009, at 9:06 PM, Nick Coghlan wrote:

> Raymond Hettinger wrote:
>> The current formatting mini-language provisions left/right/center
>> alignment, prefixes for 0b 0x 0o, and rules on when to show the
>> plus-sign.  I think it would be far more useful to provision a simple
>> way of specifying a thousands separator.
>>
>> Financial users in particular find the locale approach to be  
>> frustrating
>> and non-obvious.  Putting in a thousands separator is a common task  
>> for
>> output destined to be read by non-programmers.
>
> +1 for the general idea.
>
> A specific syntax proposal:
>
>  [[fill]align][sign][#][0][minimumwidth][,sep][.precision][type]
>
> 'sep' is the new field that defines the thousands separator. It  
> appears
> immediately before the precision specifier and starts with a leading  
> comma.
>
> I believe this syntax is unambiguous and backwards compatible because
> the only other place a comma might appear (the fill field) is required
> to be followed by an alignment character.

You might be interested to know that in India, the commas don't come  
every 3 digits. In india, they come every two digits, after the first  
three. Thus one billion = 1,00,00,00,000. How are you gonna represent  
*that* in a formatting mini-language? :)

See also http://en.wikipedia.org/wiki/Indian_numbering_system

James