[Tutor] String representation of NULL (non type) values

[Joel Goldstick]

On Mon, Nov 4, 2013 at 5:34 AM, Ulrich Goebel <ml at fam-goebel.de> wrote:
> Hallo,
>
> from a SQLite database I get a value by SELECT s from... which normaly is a
> string, but can be the NULL value, wich means it is not defined. To put the
> value into a form (made by QT) I need a string representation.
>
> str(s) gives either the string itself (which is good) or "None" (which is
> not so good) in the case of NULL. Instead of "None" I would prefer an empty
> string "". How to get that?
>
> Possibly there is a build in function smart(s1, s2, s3,...) which returns
> the first s which is a useable string, or even "" if there isn't any string
> in the arguments?
>
> Thanks for help
> Ulrich
>
>
> --
> Ulrich Goebel
> Paracelsusstr. 120, 53177 Bonn
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In python you can do this:

>>> a = None
>>> b = a or ""
>>> b
''
>>> a = "text here"
>>> b = a or ""
>>> b
'text here'
>>>

If a is None (false in python), it will check the value after or and
return that.  If a is a string (hence true in python) it will return
the string

-- 
Joel Goldstick
http://joelgoldstick.com