[Tutor] A CSV field is a list of integers - how to read it as such?

[Dave Angel]

On 03/06/2013 09:05 PM, DoanVietTrungAtGmail wrote:
>> Once a csv file has been read by a csv reader (such as DictReader), it's
>> no longer a csv file.
>
>
> That was an "Aha!" moment for me. The file is on disk, each row of it is in
> memory as a list or dict, and it's the list or dict that matters. It's so
> obvious now. Thanks Dave.
>
>>
>
> a namedtuple is probably exactly what you want.
>
>
> I read this as meaning that while tuples themselves are immutable, to
> effectively modify it I simply delete it and replace it with a new tuple
> with new values. Another 'Aha!'
>

A collections.namedtuple is not the same as a tuple.  The items in it 
can be addressed either by index, or by name.  But each instance of the 
tuple does *not* waste space duplicating those names.  The names are 
stored once per type of namedtuple

http://docs.python.org/2/library/collections.html#collections.namedtuple

Look at the example following the comment:
""" Named tuples are especially useful for assigning field names to 
result tuples returned by the csv or sqlite3 modules:"

And an instance created through collections.namedtuple has a useful method:

somenamedtuple._replace(kwargs)
Return a new instance of the named tuple replacing specified fields with 
new values:

-- 
DaveA