csv format to DBase III format

coriolis_wong at yahoo.com.hk coriolis_wong at yahoo.com.hk
Fri Jan 6 09:33:30 CET 2006


Peter Otten wrote:
> coriolis_wong at yahoo.com.hk wrote:
>
> > I need to transfer csv format file to DBase III format file.
> > How do i do it in Python language?
>
> http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/362715
>
> Peter

Hi,

I create a dbf file, it can be opened by Excel but it cannot be opened
by Access. Where is the error in my script. My script is as follows,

def dbfwriter(f, fieldnames, fieldspecs, records):
    """ Return a string suitable for writing directly to a binary dbf
file.

    File f should be open for writing in a binary mode.

    Fieldnames should be no longer than ten characters and not include
\x00.
    Fieldspecs are in the form (type, size, deci) where
        type is one of:
            C for ascii character data
            M for ascii character memo data (real memo fields not
supported)
            D for datetime objects
            N for ints or decimal objects
            L for logical values 'T', 'F', or '?'
        size is the field width
        deci is the number of decimal places in the provided decimal
object
    Records can be an iterable over the records (sequences of field
values).

    """
    # header info
    ver = 3
    now = datetime.datetime.now()
    yr, mon, day = now.year-1900, now.month, now.day
    numrec = len(records)
    numfields = len(fieldspecs)
    lenheader = numfields * 32 + 33
#   lenrecord = sum(field[1] for field in fieldspecs) + 1
    num = 0
    for field in fieldspecs :
         num = num + int(field[1])

    lenrecord = num + 1

    hdr = struct.pack('<BBBBLHH20x', ver, yr, mon, day, numrec,
lenheader, lenrecord)
    f.write(hdr)

    # field specs
    for name, (typ, size, deci) in itertools.izip(fieldnames,
fieldspecs):
#       name = name.ljust(11, '\x00')
        name = name.ljust(11)
        fld = struct.pack('<11sc4xBB14x', name, typ, size, deci)
        f.write(fld)

    # terminator
    f.write('\r')

    # records
    for record in records:
        f.write(' ')                        # deletion flag
        for (typ, size, deci), value in itertools.izip(fieldspecs,
record):
            if typ == "N":
#               value = str(value).rjust(size, ' ')
                value = str(value).rjust(size)
            elif typ == 'D':
#               value = value.strftime('%Y%m%d')
                value = value
            elif typ == 'L':
                value = str(value)[0].upper()
            else:
#               value = str(value)[:size].ljust(size, ' ')
                value = str(value)[:size].ljust(size)
            assert len(value) == size
            f.write(value)

    # End of file
    f.write('\x1A')
    f.close()


# -------------------------------------------------------
# Example calls
if __name__ == '__main__':

    import sys, csv
    from cStringIO import StringIO
#   from operator import itemgetter


    # Create a new DBF
#   f = StringIO()

    f = open('test.dbf','w')
    fieldnames = ['CUSTOMER_ID','EMPLOY_ID','ORDER_DATE','ORDER_AMT']
    fieldspecs = [('C',11,0),('C',11,0),('D',8,0),('N',12,2)]
    records = [['MORNS','555','19950626','17.40'],\
                    ['SAWYH','777','19950629','97.30'],\
                    ['WALNG','555','19950522','173.40']]


    dbfwriter(f, fieldnames, fieldspecs, records)



William




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