Exception, Lambda, dict - Python example

Exceptions example from a Well House Consultants training course
More on Exceptions [link]

This example is described in the following article(s):
• Exception, Lambda, Generator, Slice, Dict - examples in one Python program - [link]

Source code: topstats Module: Y109

# Exception, Lambda, dict

usage = {}

# Finding most and least used UK railway stations

for record in open("railstats.xyz"):
        els = record.split("\t")
        name = els[6]
        try:
                passengers = int(els[-1])
                usage[name] = passengers
        except NameError:
                print "oops"
        except ValueError:
                pass
        except:
                print "Oh Sh..dear"

places = usage.keys()
places.sort(lambda x,y: usage[x] - usage[y])

print "Most used 20"
for place in places[-20:]:
        print usage[place],place

print "Least used 20"
for place in places[:20]:
        print usage[place],place

""" Sample Output

Most used 20
15093655 Fenchurch Street
17758808 Clapham Junction
18020645 St.Pancras
18413982 Liverpool Central
19121724 Glasgow Queen Street
19312458 Edinburgh
19841402 Manchester Piccadilly
19881243 East Croydon
20229239 Cannon Street
21978372 Leeds
23809949 Glasgow Central
24817616 King's Cross
25267757 Birmingham New Street
29104198 Paddington
30068092 Euston
36459945 Charing Cross
48723068 London Bridge
51596155 Liverpool Street
70224543 Victoria
86397666 Waterloo
Least used 20
42 Coombe
68 Tees-Side Airport
76 Reddish South
90 Barry Links
106 Sugar Loaf
116 Breich
154 Buckenham
156 Altnabreac
162 Chapelton
166 Pilning
166 Elton & Orston
184 Scotscalder
190 Golf Street
202 Achanalt
204 Kildonan
204 Falls Of Cruachan
220 Kirton Lindsey
252 Rawcliffe
268 Locheilside
268 Acklington
munchkin:pf13 grahamellis$

"""

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* Learning to program in Python
* Python Programming
* Intermediate Python
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