coercing to Unicode: need string or buffer, NoneType found

[Jon Bowlas]

Ahh yes there are a couple of dodgy records that seem to have been added.

many thanks.

Jon
----- Original Message ----- 
From: "Peter Otten" <__peter__ at web.de>
Newsgroups: comp.lang.python
To: <python-list at python.org>
Sent: Thursday, July 27, 2006 11:22 AM
Subject: Re: coercing to Unicode: need string or buffer, NoneType found


> Jon Bowlas wrote:
>
>> I wrote this script in Zope some time ago and it worked for a while, but
>> now I'm getting the following error:
>> TypeError: coercing to Unicode: need string or buffer, NoneType found
>>
>> Here's my script:
>>
>> results = context.module_retriever().tuples() # call to ZSQLMethod
>> converted = []
>> for result in results:
>>    result = list(result) # make a list from the tuple
>>    for i in range(len(result)):
>>     # for each element in the listified tuple, make decode to a
>>     # unicode from the latin-1 string
>>     result[i] = unicode(result[i], 'latin-1')
>>    converted.append(tuple(result)) # tuplify again
>> return converted
>>
>> Where module_retriever is a simple Z SQL method that returns a module
>> title and a module code.
>> So results = context.module_retriever().tuples() returns:
>> [('Developmental Neurobiology', 'ANAT2008'), ('Neuroanatomy',
>> 'ANAT2009'),('etc...', 'etc..'),..]So I was hoping someone might be able
>> to identify what I've done wrong here. It is a little mistifying as to 
>> why
>> it's suddenly stopped working though.CheersJon
>
> This may be an indication that in your database you have a record with a
> None value, e. g.
>
>        [('Developmental Neurobiology', 'ANAT2008'),
>         ('Neuroanatomy', 'ANAT2009'),
>         ('Man in black', None)])
>
> and most likely the right fix is to correct the database entry and make 
> sure
> that no new such records can be entered into it.
>
> If that is not possible, a quick fix would be to replace your unicode() 
> call
> with something that special-cases None:
>
> def from_latin(s):
>    if s is None:
>        return None # or maybe 'return u""', if your app expects a unicode
>                    # string
>    return unicode(s, "latin-1")
>
> By the way, in recent Python your snippet might become
>
>    converted = []
>    for record in results:
>        # prior to 2.4: tuple([...])
>        converted.append(tuple(from_latin(field) for field in record))
>    return converted
>
> Peter
>
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