On Thu, Oct 06, 2005 at 10:28:23PM -0400, Kent Johnson wrote:
>William O'Higgins Witteman wrote:
>> I'm trying to traverse a dictionary looking for partial matches of the
>> key, and I'm not sure how. Here's a sample dictionary:
>>
>> dict = {00001234 : value1, 20051234 : value2, 20071234 : value3}
>>
>> Here's what I'm trying to do:
>>
>> for key in dict:
>> if key == 0000???? or key == 2005????:
>
> if key.startswith('0000') or key.startswith('2005'):
This is perfect! Where do I read about things like this? I've been
spending a bunch of time with the python.org documentation, "A Byte of
Python" and "Dive Into Python", but I didn't run across this.
>or with a regular expresion:
> if re.match('0000|2005', key):
This is good too, and it shows me the syntax (which I had trouble with).
>> do something with dict[key]
>>
>> The challenge is that I only care about the first four digits of the key
>> for the purpose of this match - is there a way to express this? I could
>> probably create a wrapper dictionary using just the first four digits of
>> the key as they key, and containing the original key:value pair as a
>> list within it, but that seems cumbersome. Any one have a suggestion?
>
>If you have a *lot* of keys and need more speed, that might be a good
>optimization. For a small dict, just use startswith().
Should I compile the regex to further increase the speed?
Thanks for the help.
--
yours,
William
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