[newbie questions] if conditions - if isset - if empty

[MRAB]

On 14/04/2012 23:45, Chris Angelico wrote:
> On Sun, Apr 15, 2012 at 8:41 AM, Mahmoud Abdel-Fattah
> <accounts at abdel-fattah.net>  wrote:
>>  item['author_brand'] = author_brand.group(2) if type(author_brand) != None
>>  else ''
>
> Almost there! :)
>
> None is a singleton, not a type; you don't need to check
> type(author_brand) but rather its identity. Use "author_brand is not
> None" for your condition and it should work like you're expecting. In
> this case, you can actually just use "author_brand" as your condition
> (no quotes, of course), as None evaluates as false.
>
re.match(...) returns either a match object or None. In a condition, a
match object always evaluates as True and None always evaluates as
False.