frequency of values in a field

[Paul Rubin]

noydb <jenn.duerr at gmail.com> writes:
>> counts = {}
>> for thing in long_list:
>>   key = make_key(thing)
>>   if key in counts:
>>     counts[key] += 1
>>   else:
>>     counts[key] = 1

counts = {}
for thing i long_list:
  key = make_key(thing)
  counts[key] = 1 + counts.get(key, 0)

> How do you add all the records in the particular field of interest
> into long_list?

I don't understand this question.  Where are they coming from?