ch02: automated tests

02-array-seq/metro_lat_long.py

@@ -1,3 +1,16 @@
+"""
+metro_lat_long.py
+
+Demonstration of nested tuple unpacking::
+
+    >>> main()
+                    |   lat.    |   long.  
+    Mexico City     |   19.4333 |  -99.1333
+    New York-Newark |   40.8086 |  -74.0204
+    Sao Paulo       |  -23.5478 |  -46.6358
+
+"""
+
 metro_areas = [
     ('Tokyo', 'JP', 36.933, (35.689722, 139.691667)),   # <1>
     ('Delhi NCR', 'IN', 21.935, (28.613889, 77.208889)),
@@ -6,8 +19,12 @@ metro_areas = [
     ('Sao Paulo', 'BR', 19.649, (-23.547778, -46.635833)),
 ]
 
-print('{:15} | {:^9} | {:^9}'.format('', 'lat.', 'long.'))
-fmt = '{:15} | {:9.4f} | {:9.4f}'
-for name, cc, pop, (latitude, longitude) in metro_areas:  # <2>
-    if longitude <= 0:  # <3>
-        print(fmt.format(name, latitude, longitude))
+def main():
+    print('{:15} | {:^9} | {:^9}'.format('', 'lat.', 'long.'))
+    fmt = '{:15} | {:9.4f} | {:9.4f}'
+    for name, cc, pop, (latitude, longitude) in metro_areas:  # <2>
+        if longitude <= 0:  # <3>
+            print(fmt.format(name, latitude, longitude))
+
+if __name__ == '__main__':
+    main()