[Tutor] Multi-Dimensional Dictionary that contains a 12 element list.

[Kent Johnson]

Paul Kraus wrote:
> Here is the code that I used. Its functional and it works but there has got to 
> be some better ways to do a lot of this. Transversing the data structure 
> still seems like I have to be doing it the hard way.
> 
> The input data file has fixed width fields that are delimited by pipe.
> So depending on the justification for each field it will either have leading 
> or ending whitespace.
> #############################
> import re 
> import string
> results = {}
> def format_date(datestring):
>     (period,day,year) = map(int,datestring.split('/') )
>     period += 2
>     if period == 13: period = 1; year += 1
>     if period == 14: period = 2; year += 1
   if period > 12: period -= 12; year += 1

>     if year > 80:
>         year = '19%02d' % year
>     else:
>         year = '20%02d' % year
>     return (year,period)
> 
> def format_qty(qty,credit,oreturn):
>     qty = float(qty)
>     if credit == 'C' or oreturn == 'Y':
>         return qty * -1
>     else:
>         return qty
> 
> textfile = open('orders.txt','r')
> for line in textfile:
>     fields = map( string.strip, line.split( '|' ) )
>     fields[4] = format_qty(fields[ 4 ],fields[ 1 ], fields[ 2 ] )
   qty = format_qty(fields[ 4 ],fields[ 1 ], fields[ 2 ] )
would be clearer in subsequent code.

>     (year, period) = format_date( fields[7] )
>     for count in range(12):
>         if count == period:
>             if results.get( ( year, fields[6], count), 0):
>                 results[ year,fields[6], count] += fields[4]
>             else:
>                 results[ year,fields[6],count] = fields[4]

The loop on count is not doing anything, you can use period directly. 
And the test on results.get() is not needed, it is safe to always add:
   key = (year, fields[6], period)
   results[key] = results.get(key, 0) + qty
> 
> sortedkeys = results.keys()
> sortedkeys.sort()
> 
> for keys in sortedkeys:
>     res_string = keys[0]+'|'+keys[1]
>     for count in range(12):
>         if results.get((keys[0],keys[1],count),0):
>             res_string += '|'+str(results[keys[0],keys[1],count])
>         else:
>             res_string += '|0'
>     print res_string

This will give you duplicate outputs if you ever have more than one 
period for a given year and field[6] (whatever that is...). OTOH if you 
just show the existing keys you will not have entries for the 0 keys. So 
maybe you should go back to your original idea of using a 12-element 
list for the counts.

Anyway in the above code the test on results.get() is not needed since 
you just use the default value in the else:
   res_string += str(results.get((keys[0],keys[1],count),0))

> </code>
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