High level csv reader

John Machin sjmachin at lexicon.net
Wed Nov 1 11:17:55 CET 2006


George Sakkis wrote:
> It occured to me that most times I read a csv file, I'm often doing
> from scratch things like assigning labels to columns, mapping fields to
> the appropriate type, ignoring some fields, changing their order, etc.
> Before I go on and reinvent the wheel, is there a generic high level
> wrapper around csv.reader that does all this ?
>

Hi George,

Firstly one thing to remember: if you are going to reinvent the wheel,
don't forget to also reinvent the axle :-)

AFAIK there is no such animal.

I would need a lot of persuasion that a wrapper or toolbox wasn't just
overhead with little benefit. For example, ignoring some fields and/or
changing the order of others can be done rather simply:

|  >>> inrow
| ['a', 'b', 'c', 'd', 'e', 'f']
Suppose we want to ignore the "vowels" and reverse the order of the
others:
| >>> outrow = list(inrow[k] for k in (5, 3, 2, 1))
| >>> outrow
| ['f', 'd', 'c', 'b']

I don't see the value in creating (and documenting!) a one-line
function

def gather_list_items(input_list, item_map):
    return list(input_list[k] for k in item_map)

NB something like this is already in the mx kit somewhere IIRC.

Cheers,
John




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