CSV(???)

[Neil Cerutti]

On 2007-02-23, David C  Ullrich <ullrich at math.okstate.edu> wrote:
> Is there a csvlib out there somewhere?
>
> And/or does anyone see any problems with
> the code below?
>
> What csvline does is straightforward: fields
> is a list of strings. csvline(fields) returns
> the strings concatenated into one string
> separated by commas. Except that if a field
> contains a comma or a double quote then the
> double quote is escaped to a pair of double
> quotes and the field is enclosed in double
> quotes.
>
> The part that seems somewhat hideous is
> parsecsvline. The intention is that
> parsecsvline(csvline(fields)) should be
> the same as fields. Haven't attempted
> to deal with parsecsvline(data) where
> data is in an invalid format - in the
> intended application data will always
> be something that was returned by
> csvline. It seems right after some
> testing... also seems blechitudinous.
>
> (Um: Believe it or not I'm _still_ using python 1.5.7. So
> comments about iterators, list comprehensions, string methods,
> etc are irrelevent. Comments about errors in the algorithm
> would be great. Thanks.)

Two member functions of indexedstring are not used: next and
lookahead. __len__ and __getitem__ appear to serve no real
purpose.

> def parsecsvline(csvline):
>   """Inverts csvline(). Assumes csvline is valid, ie
>   is something as returned by csvline(); output undefined
>   if csvline is in invalid format"""
>
>   s = indexedstring(csvline)
>   res = []
>
>   while not s.eos():
>    res.append(s.getfield())
>
>   return res

You'll be happy to know that iterators and list comprehensions
will make your code better after you upgrade. ;-)

In the meantime, I think your (relative lack of) error handling
is OK. GIGO, as they say (garbage in, garbage out).

-- 
Neil Cerutti