On Wed, 24 Jan 2007 11:51:27 -0800, metaperl wrote:
> Ok, I have a module called textgen.py. The point of this module is to
> generate a csv file from an array of dictionaries.
You probably should use the csv module to do the grunt work, leaving your
module just to massage the dicts into a form that csv can handle.
> As I iterate through
> each dictionary, I "massage" the dictionary values before writing them
> out to csv. Now, for one dictionary entry, I have the following code:
>
> if dict_key == 'PCN':
> fields = dict_val.split("/")
> mo = re.match( '(\w{2})(\d{2})(\d{2})' , fields[1] )
> if mo:
> dict_val = "%s/%s%s/%s" % (fields[0], mo.group(1),
> mo.group(3),
> fields[2][1:])
> else:
> dict_val = dict_val
Your indentation seems very inconsistent -- the lines starting with
"fields = ..." and "mo = ..." should have the same indentation.
The line "dict_val = dict_val" is a no-op. You could just as easily write
that as "pass", or even better, leave out the entire else clause.
Reading between the lines, it sounds like you have a mass of if...elif
clauses, like this:
if dict_key == 'PCN':
# some processing
elif dict_key == 'NCP':
# some different processing
elif ...
# blah blah blah
else:
# default processing
This is an excellent candidate for dictionary-based dispatching. First,
write a function for each processing block:
def process_PCN(value):
# do stuff to value
return result
and then create a dispatch table:
dispatcher = {"PCN": process_PCN, "NCP": process_NCP, ...}
Now your huge if...elif block becomes one line:
# no default processing
dispatcher[dict_key](dict_value)
# with default processing
dispatcher.get(dict_key, process_default)(dict_value)
> Ok, so now here is what has happened. This code was based on the
> assumption that dict_val would have 2 forward slashes in it. It turns
> out that I need to follow a different process of massaging when no
> slashes are present. A naive solution would be something like:
>
> if dict_key == 'PCN':
> fields = dict_val.split("/")
> if fields == 3:
That can't possibly work. fields is a list, not an integer.
I think you want if len(fields) == 3.
> dict_val = pcn_three(fields) # where pcn_three
> is the code above
> else:
> # new logic
>
> But I am wondering if I should abstract the flow of control into a
> class or something.
Nope. Abstract it into functions.
--
Steven.
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