Help cleaning up some code

andrew cooke andrew at acooke.org
Sun Mar 8 12:52:23 CET 2009


andrew cooke wrote:
> odeits wrote:
>> On Mar 7, 1:07 pm, Scott David Daniels <Scott.Dani... at Acm.Org> wrote:
>>> odeits wrote:
>>> > I am looking to clean up this code... any help is much appreciated.
>>> > Note: It works just fine, I just think it could be done cleaner.
>>>
>>> > The result is a stack of dictionaries. the query returns up to
>>> > STACK_SIZE ads for a user. The check which i think is very ugly is
>>> > putting another contraint saying that all of the ni have to be the
>>> > same.
>>>
>>> Well, the obvious way to get your constraint is by changing your SQL,
>>> but if you are going to do it by fetching rows, try:
>>>
>>>      FIELDS = 'ni adid rundateid rundate city state status'.split()
>>>      ni = UNSET = object() # use None unless None might be the value
>>>      stack = []
>>>      rows = self.con.execute(adquerystring,
>>> (user,STACK_SIZE)).fetchall()
>>>      for row in rows:
>>>          ad = dict()
>>>          for field in FIELDS:
>>>              ad[field] = row[field]
>>>          for field in 'city', 'state':
>>>              if ad[field] is None:
>>>                  ad[field] = 'None'
>>>          if ni != ad['ni']:
>>>              if ni is UNSET:
>>>                  ni = ad['ni']
>>>              else:
>>>                  break
>>>          stack.append(ad)
>>>
>>> --Scott David Daniels
>>> Scott.Dani... at Acm.Org
>>
>> Taking from several suggestions this is what i have come up with for
>> now:
>>
>>          for row in  ifilter(lambda r: r['ni'] == rows[0]['ni'],rows):
>
> not sure what version of python you're using, but it would be more natural
> in recent python to write that as:
>
>          for row in (r for r in rows if r['ni'] == rows[0]['ni']):

or even just

          for row in rows:
            if row['ni'] == rows[0]['ni']:

(unfortunately it seems that putting that on a single line is not valid
syntax)

andrew

>
> (the () create a generator for you).
>
> andrew
>
>
>>             ad = dict()
>>
>>             keys = row.keys() # if python 2.6
>>             keys =
>> ['ni','adid','rundateid','rundate','city','state','status'] # if
>> python 2.5
>>
>>             for index in row.keys():
>>                 if row[index] is None:
>>                     ad[index] = 'None'
>>                 else:
>>                     ad[index] = row[index]
>>             stack.append(ad)
>>             print row
>>
>> the test to see if the ad is valid is placed in the ifilter so that I
>> dont build the dictionary unnecessarily. and the None special case is
>> fairly simple to read now. The None case would even be irrelevant if i
>> could get the damn xmlrpc to allow null. sigh. anyhow. thanks for all
>> of your input, it is definitely better than it was ;)
>> --
>> http://mail.python.org/mailman/listinfo/python-list
>>
>>
>
>





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