Value Error: could not convert string to float

[Kevin5013HD]

Hi, you have developed an excelent package for readinf .dbf but I have had many issues reading one of them. I want to keep just 2 columns of the .dbf but first I have to load it to then read for delete columns later but at this step, I got a Value Error of one of the registers of the .dbf which is part of the columns I want to delete.

In fact, first I got a Value Error with strange characters but ,modifying the function 'parseN' it was converted that strange character to 'nz'

Thanks for helping me in this issue, I hope get your answer.

[TinyHandsome]

I have my way to solve this problem. You can change the source code in field_parser.p.
At code line 170:
except ValueError:
if not data.strip():
return None

# next two line, I insert my code to solve the problem.
elif data.strip() == b'.':
return '.'

else:
return float(data.replace())

It's my first time to answer question, I'm so sorry my English is so poor, and I don't know how to indent code. I hope my answer can solve your problem. If you have any question, you can contact me.

[nohlson]

I know this is an old thread but I just encountered this issue while working on migrating a legacy database.

I checked and the legacy software simply interprets these b'.' values as 0.0 and doing a bit of research there are apparently some implementations that will use the b'.' as a null character. I tried to find some documentation to justify bringing this into the mainline parser but since it seems to be a more niche way to encode null it's probably best to not.

You could use a custom parser class to override the parseN method and return None for this case:

from dbfread import DBF, FieldParser

class CustomFieldParser(FieldParser):
    def parseN(self, field, data):
        """Parse numeric field (N)

        Returns int, float or None if the field is empty.
        """
        # In some files * is used for padding.
        data = data.strip().strip(b'*')

        try:
            return int(data)
        except ValueError:
            if not data.strip():
                return None
            elif data.strip() == b'.':
                return None
            else:
                # Account for , in numeric fields
                return float(data.replace(b',', b'.'))

table = DBF(filepath, parserclass=CustomFieldParser, load=True)