how can i change the text delimiter

[John Machin]

sonald wrote:
> Hi,
> I am using
> Python version python-2.4.1 and along with this there are other
> installables
> like:
> 1. fastcsv-1.0.1.win32-py2.4.exe

Well, you certainly didn't get that from the object-craft website --
just go and look at their download page
http://www.object-craft.com.au/projects/csv/download.html -- stops dead
in 2002 and the latest windows kit is a .pyd for Python 2.2. As you
have already been told and as the object-craft csv home-page says,
their csv was the precursor of the Python csv module.


> 2. psyco-1.4.win32-py2.4.exe
> 3. scite-1.63-setup.exe
>
> We are freshers here, joined new... and are now into handling this
> module which validates the data files, which are provided in some
> predefined format from the third party.
> The data files are provided in the comma separated format.
>
> The fastcsv package is imported in the code...
>      import fastcsv
> and
>      csv = fastcsv.parser(strict = 1,field_sep = ',')

Aha!! Looks like some misguided person has got a copy of the
object-craft code, renamed it fastcsv, and compiled it to run with
Python 2.4 ... so you want some docs. The simplest thing to do is to
ask it, e.g. like this, but with Python 2.4 (not 2.2) and call it
fastcsv (not csv):

... command-prompt...>\python22\python
Python 2.2.3 (#42, May 30 2003, 18:12:08) [MSC 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import csv
>>> help(csv.parser)
Help on built-in function parser:

parser(...)
    parser(ms_double_quote = 1, field_sep = ',',
           auto_clear = 1, strict = 0,
           quote_char = '"', escape_char = None) -> Parser

    Constructs a CSV parser object.

        ms_double_quote
            When True, quotes in a fields must be doubled up.

        field_sep
            Defines the character that will be used to separate
            fields in the CSV record.

        auto_clear
            When True, calling parse() will automatically call
            the clear() method if the previous call to parse() raised
an
            exception during parsing.

        strict
            When True, the parser will raise an exception on
            malformed fields rather than attempting to guess the right
            behavior.

        quote_char
            Defines the character used to quote fields that
            contain the field separator or newlines.  If set to None
            special characters will be escaped using the escape_char.
##### That's what you are looking for #####
        escape_char
            Defines the character used to escape special
            characters.  Only used if quote_char is None.

>>> help(csv)
Help on module csv:

NAME
    csv - This module provides class for performing CSV parsing and
writing.

FILE
    SOMEWHERE\csv.pyd

DESCRIPTION
    The CSV parser object (returned by the parser() function) supports
the
    following methods:
        clear()
            Discards all fields parsed so far.  If auto_clear is set to
            zero. You should call this after a parser exception.

        parse(string) -> list of strings
            Extracts fields from the (partial) CSV record in string.
            Trailing end of line characters are ignored, so you do not
            need to strip the string before passing it to the parser.
If
            you pass more than a single line of text, a csv.Error
            exception will be raised.

        join(sequence) -> string
            Construct a CSV record from a sequence of fields.
Non-string
            elements will be converted to string.

    Typical usage:

        import csv
        p = csv.parser()
        file = open('afile.csv')
        while 1:
            line = file.readline()
            if not line:
                break
            fields = p.parse(line)
            if not fields:
                # multi-line record
                continue
            # process the fields
[snip remainder of docs]
>
> can u plz tell me where to find the parser function definition, (used
> above)
> so that if possible i can provide a parameter for
> text qualifier or text separator or text delimiter..
> just as {field_sep = ','} (as given above)
>
> I want to handle string containing double quotes (")
> but the problem is that the default text qualifier is double quote
>
> Now if I can change the default text qualifier... to say pipe (|)
> the double quote inside the string may be ignored...
> plz refer to the example given in my previous query...
>

It *appears* from this message that you have data already in a file,
and that data is *NOT* (as some one has already told you) in standard
CSV format.

Let me explain: The magic spell for quoting a field in standard CSV
format is:
quote = '"'
sep = ','
twoquotes = quote + quote
if quote in fld:
    fld = quote + fld.replace(quote, twoquotes) + quote
elif sep in fld:
    fld = quote + fld + quote

Note carefully that if the quote character appears in the raw input
data, it must be *doubled* in the output. If it is not, the standard
reader can't decode the input unambiguously. If is possible that the
using ms_double_quote=0 with the [fast]csv module will do the job for
you. If not, it is possible, if the original data contains *pairs* of
quotes e.g. -- He said "Hello" to his friend -- to decode that using a
different state machine. If that's what you've got, e-mail me; I may be
able to help. However the example you gave had just one quote :-(

*But* are you reading or writing this data? On one hand you say that
you are getting the data from a 3rd party and can't change it [which
implies that you are reading] but on the other hand you want to know
how to tell the [fast]csv module use a "|" as the quote character; that
would be appropriate under two circumstances (1) you are reading a file
that already has "pipe" as the quote character (2) you want to create a
file that quotes using "pipe" ... IOW, it's not guaranteed to work for
reading an existing file that uses " as the quote character. If there
is a pipe character in the original data, it will fail. If (more
likely) there are commas in the original data, then you will get one
extra field per comma.

A quick simple question: after the above csv = fastcsv.parser(.......),
does it do csv.parse(.....) or csv.join(...)???? Can you see any
fread() or fwrite() calls in the code??? If so, which???

HTH -- but you will have to describe what's going on a lot more
precisely.

Cheers,
John