plane_routes.py

# coding: utf-8

# In[76]:

from collections import defaultdict

merge_cities = {
    'NYC': ['EWR', 'JFK', 'LGA'],
}
airport_to_cities = dict()
for city in merge_cities:
    for airport in merge_cities[city]:
        airport_to_cities[airport] = city

international = set(['AMS', 'CDG', 'YYZ', 'FRA', 'IST', 'PEK', 'DME', 'MUC', 'DXB', 'LHR', 'LGW'])

all_routes = defaultdict(set)

with open("/home/dierks/routes.dat") as routes:
    for route_line in (line.strip() for line in routes):
        (airline, airline_id, src, src_id, dest, dest_id, codeshare, stops, equipment) = route_line.split(",")
        if stops <> "0":
            continue
        if src in international or dest in international:
            continue
        if src in airport_to_cities:
            src = airport_to_cities[src]
        if dest in airport_to_cities:
            dest = airport_to_cities[dest]
        all_routes[src].add(dest)


# In[77]:

len(all_routes)


# In[78]:

for src in all_routes.keys():
    for dest in all_routes[src]:
        if src not in all_routes[dest]:
            all_routes[dest].add(src) # pretend you can get back


# In[79]:

most_connected = sorted(all_routes.keys(), key = lambda k: len(all_routes[k]), reverse = True)


# In[80]:

most_connected[0:20]


# In[81]:

# find a greedy clique
def greedy(seed):
    clique = set()
    clique.update(seed)
    for airport in most_connected:
        if airport in clique:
            next
        if all((dest in all_routes[airport] for dest in clique)):
            clique.add(airport)
    return clique


# In[82]:

us_set = greedy(['NYC', 'LAX', 'SEA', 'ATL'])
us_set


# In[83]:

all_routes["DCA"].difference(all_routes["IAD"])


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