[Tutor] RE: Tutor Digest, Vol 3, Issue 14
Raymond Hettinger
python at rcn.com
Mon May 10 12:24:40 EDT 2004
> 1. What is the data structure below called? Apart from G :-P Is it an
> array, a list or something else. The original article was very vague
on
> the commenting. See bottom of email for URL.
>
> G = {'s':{'u':10, 'x':1},
> 'u':{'v':1, 'x':2},
> 'v':{'y':4},
> 'x':{'u':3, 'v':9, 'y':2},
> 'y':{'s':7, 'v':6}
> }
It is a directed graph, with path weights.
Think of airline routes.
>From airport S you can fly to either airport u or airport x. It takes
10 hours to get to u but only one hour to get to x.
> 2. How would I alter the above data structure such that all instances
of
> 'x' ends up being equal to 5. As per sample below.
>
> {'s':{'u':10, 'x':5},
> 'u':{'v':1, 'x':5},
> 'v':{'y':4},
> 'x':{'u':3, 'v':9, 'y':2},
> 'y':{'s':7, 'v':6}
> }
for airpost, destinations in G:
for dest, cost in destinations:
if dest == 'x':
destinations['x'] = 5
Raymond Hettinger
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