On Sun, 14 Mar 2010 10:06:49 am Ray Parrish wrote:
> Hello,
>
> I am stuck on the following -
>
> # Define the Dates{}
> dictionary structure as a dictionary
> # containing two dictionaries,
> each of which contains a list.
> Dates =
> {Today:{ThisIPAddress:[]},
> Tomorrow:{ThisIPAddress:[]}}
>
> How do I pass this declaration empty values for
> Today, Tomorrow, and ThisIPAddress to initially
> clare it?
You don't. Once you create a key, you can't modify it. So if you create
an empty value for Today etc., it stays empty.
> The idea behind the structure is to sort through a
> server log that contains entries for two dates,
[...]
Just work out the dates before hand, and populate the dictionary that
way:
today = "2010-03-13"
tomorrow = "2010-03-14"
thisIP = "123.456.789.123"
entries = {today: {thisIP: []}, tomorrow: {thisIP: []}}
Or don't pre-populate the dict at all.
entries = {}
for line in logfile:
# Process the line to get a date, an IP address, and visitor
date = ...
address = ...
visitor = ...
entry = entries.get(date, {})
x = entry.get(address, {})
x.append(visitor)
entry[address] = x
entries[date] = entry
The trick is to use get to look up the dictionary:
entries.get(date, {})
looks up date in entries, and if it isn't found, it returns an empty
dict {} instead of failing. Similarly for looking up the IP address.
--
Steven D'Aprano
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
http://mail.python.org/mailman/listinfo/tutor
