counting preferences

count1.py

@@ -0,0 +1,16 @@
+import csv
+from collections import defaultdict
+
+def ice_cream_counts(path):
+    """Returns gender/preference counts from csv in path."""
+    counts = {'m': defaultdict(int), 'f': defaultdict(int)}
+
+    with open(path) as csvfile:
+        reader = csv.DictReader(csvfile)
+        for row in reader:
+            counts[row['gender']][row['preference']] += 1
+
+    return counts
+
+counts = ice_cream_counts('ice-cream.csv')
+print(counts)

count2.py

@@ -0,0 +1,16 @@
+import csv
+from collections import defaultdict
+
+def ice_cream_counts(path):
+    """Returns gender/preference counts from csv in path."""
+    counts = {'m': defaultdict(int), 'f': defaultdict(int)}
+
+    with open(path) as csvfile:
+        reader = csv.DictReader(csvfile)
+        for row in reader:
+            counts[row['gender']][row['preference']] += 1
+
+    return counts
+
+counts = ice_cream_counts('ice-cream.csv')
+print(counts)

read3.py

@@ -5,6 +5,8 @@ def read_data(path):
     with open(path) as csvfile:
         reader = csv.DictReader(csvfile)
         for row in reader:
+            assert row['gender'] in 'mf'
+            assert row['preference'] in 'ps'
             print(row['gender'], row['preference'])
 
 read_data('ice-cream.csv')