updated contents from Atlas repo

functions/attrgetter_demo.rst

@@ -0,0 +1,31 @@
+>>> metro_data = [
+...     ('Tokyo', 'JP', 36.933, (35.689722, 139.691667)),
+...     ('Delhi NCR', 'IN', 21.935, (28.613889, 77.208889)),
+...     ('Mexico City', 'MX', 20.142, (19.433333, -99.133333)),
+...     ('New York-Newark', 'US', 20.104, (40.808611, -74.020386)),
+...     ('Sao Paulo', 'BR', 19.649, (-23.547778, -46.635833)),
+... ]
+# BEGIN ATTRGETTER_DEMO
+
+>>> from collections import namedtuple
+>>> LatLong = namedtuple('LatLong', 'lat long')  # <1>
+>>> Metropolis = namedtuple('Metropolis', 'name cc pop coord')  # <2>
+>>> metro_areas = [Metropolis(name, cc, pop, LatLong(lat, long_))  # <3>
+...     for name, cc, pop, (lat, long_) in metro_data]
+>>> metro_areas[0]
+Metropolis(name='Tokyo', cc='JP', pop=36.933, coord=LatLong(lat=35.689722, long=139.691667))
+>>> metro_areas[0].coord.lat  # <4>
+35.689722
+>>> from operator import attrgetter  
+>>> name_lat = attrgetter('name', 'coord.lat')  # <5>
+>>>
+>>> for city in sorted(metro_areas, key=attrgetter('coord.lat')):  # <6>
+...     print(name_lat(city))  # <7>
+...
+('Sao Paulo', -23.547778)
+('Mexico City', 19.433333)
+('Delhi NCR', 28.613889)
+('Tokyo', 35.689722)
+('New York-Newark', 40.808611)
+
+# END ATTRGETTER_DEMO