[Python-ideas] CSV api with conversion

[MRAB]

Bruce Leban wrote:
> If you do this, you'll probably want to support mapping empty values. 
> That is,
> 
> [int,str]
> 
> could map
> 
> 1,
> ,2
> 
> to 
> 
> [1,None]
> [None,'2']
> 
> or
> 
> [1,'']
> [0,'2']
> 
> I'm not sure what the defaults should be but there are reasonable use 
> cases for both.
> 
The actual values read from the CSV file are strings and you're passing
them to functions:

     int("1"), str("")
     int(""), str("2")

If you want it to return a default value instead of raising an exception
on an empty field then you should pass a conversion function which does
that, for example:

     def int_or_none(field):
         if field.strip():
            return int(field)
         else:
            return None

> --- Bruce
> http://www.vroospeak.com
> 
> 
> On Mon, Apr 12, 2010 at 3:24 AM, Éric Araujo <merwok at netwok.org 
> <mailto:merwok at netwok.org>> wrote:
> 
>     Hello list
> 
>     This API would be very useful. (I’m using Python right know to
>     filter hundreds of spreadsheets records. Loving it.)
> 
>     Suggestions:
>     1) Name the argument “converters” (it’s an iterable);
>     2) Make it a positional argument.
> 
>     Related wish: Add an argument for a row factory. Default would be
>     list, and use cases include using tuple, a named tuple class, or any
>     custom callable.
> 
>     Adding converters and rowfactory would remove the need for looping
>     over CSV reader objects and manually using row and cell converters.
> 
>     Cheers
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