Nested dictionaries trouble

[Terry Reedy]

"IamIan" <iansan at gmail.com> wrote in message 
news:1176317876.917874.58040 at n59g2000hsh.googlegroups.com...
| Hello,
|
| I'm writing a simple FTP log parser that sums file sizes as it runs. I
| have a yearTotals dictionary with year keys and the monthTotals
| dictionary as its values. The monthTotals dictionary has month keys
| and file size values. The script works except the results are written
| for all years, rather than just one year. I'm thinking there's an
| error in the way I set my dictionaries up or reference them...
|
| import glob, traceback
|
| years = ["2005", "2006", "2007"]
| months = ["01","02","03","04","05","06","07","08","09","10","11","12"]
| # Create months dictionary to convert log values
| logMonths =
| 
{"Jan":"01","Feb":"02","Mar":"03","Apr":"04","May":"05","Jun":"06","Jul":"07","Aug":"08","Sep":"09","Oct":"10","Nov":"11","Dec":"12"}
| # Create monthTotals dictionary with default 0 value
| monthTotals = dict.fromkeys(months, 0)
| # Nest monthTotals dictionary in yearTotals dictionary
| yearTotals = {}
| for year in years:
|  yearTotals.setdefault(year, monthTotals)

try yearTotals.setdefault(year, dict.fromkeys(months, 0))
so you start with a separate subdict for each year instead of 1 for all.

tjr