Latin-1 and the unicode factory in Python

Question

I have a Python 2.6 script that is gagging on special characters, encoded in Latin-1, that I am retrieving from a SQL Server database. I would like to print these characters, but I'm somewhat limited because I am using a library that calls the unicode factory, and I don't know how to make Python use a codec other than ascii.

The script is a simple tool to return lookup data from a database without having to execute the SQL directly in a SQL editor. I use the PrettyTable 0.5 library to display the results.

The core of the script is this bit of code. The tuples I get from the cursor contain integer and string data, and no Unicode data. (I'd use adodbapi instead of pyodbc, which would get me Unicode, but adodbapi gives me other problems.)

x = pyodbc.connect(cxnstring)
r = x.cursor()
r.execute(sql)

t = PrettyTable(columns)
for rec in r:
    t.add_row(rec)
r.close()
x.close()

t.set_field_align("ID", 'r')
t.set_field_align("Name", 'l')
print t

But the Name column can contain characters that fall outside the ASCII range. I'll sometimes get an error message like this, in line 222 of prettytable.pyc, when it gets to the t.add_row call:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xed in position 12: ordinal not in range(128)

This is line 222 in prettytable.py. It uses unicode, which is the source of my problems, and not just in this script, but in other Python scripts that I have written.

for i in range(0,len(row)):
    if len(unicode(row[i])) > self.widths[i]:   # This is line 222
        self.widths[i] = len(unicode(row[i]))

Please tell me what I'm doing wrong here. How can I make unicode work without hacking prettytable.py or any of the other libraries that I use? Is there even a way to do this?

EDIT: The error occurs not at the print statement, but at the t.add_row call.

EDIT: With Bastien Léonard's help, I came up with the following solution. It's not a panacea, but it works.

x = pyodbc.connect(cxnstring)
r = x.cursor()
r.execute(sql)

t = PrettyTable(columns)
for rec in r:
    urec = [s.decode('latin-1') if isinstance(s, str) else s for s in rec]
    t.add_row(urec)
r.close()
x.close()

t.set_field_align("ID", 'r')
t.set_field_align("Name", 'l')
print t.get_string().encode('latin-1')

I ended up having to decode on the way in and encode on the way out. All of this makes me hopeful that everybody ports their libraries to Python 3.x sooner than later!

Answer 1

Add this at the beginning of the module:

# coding: latin1

Or decode the string to Unicode yourself.

[Edit]

It's been a while since I played with Unicode, but hopefully this example will show how to convert from Latin1 to Unicode:

>>> s = u'ééé'.encode('latin1') # a string you may get from the database
>>> s.decode('latin1')
u'\xe9\xe9\xe9'

[Edit]

Documentation:
http://docs.python.org/howto/unicode.html
http://docs.python.org/library/codecs.html

Answer 2

Maybe try to decode the latin1-encoded strings into unicode?

t.add_row((value.decode('latin1') for value in rec))