<p>使用<code>collections.defaultdict</code>和<code>Counter</code></p>
<p><strong>例如:</strong></p>
<pre><code>from collections import defaultdict, Counter
n = int(input())
result = defaultdict(Counter)
for i in range(1, n+1):
input_row = input()
input_parts = input_row.split(' -> ')
color = input_parts[0]
items = input_parts[1].split(',')
#for item in items:
# result[color] += Counter((item,))
result[color] += Counter(items) #Thanks Sam Mason
print(result)
</code></pre>
<p><strong>输出:</strong></p>
<pre><code>defaultdict(<class 'collections.Counter'>,
{'Blue': Counter({'dress': 2, 'gloves': 1, 'jeans': 1, 'hat': 1}),
'White': Counter({'briefs': 1, 'tanktop': 1}),
'Gold': Counter({'t-shirt': 1, 'dress': 1, 'boxers': 1})})
</code></pre>
<hr/>
<p><em>无进口</em></p>
<pre><code>n = int(input())
result = {}
for i in range(1, n+1):
input_row = input()
input_parts = input_row.split(' -> ')
color = input_parts[0]
items = input_parts[1].split(',')
if not color in result:
result[color] = {}
for item in items:
if item not in result[color]:
result[color].update({item: 0}) #to update dict use the dict.update() methid
result[color][item] += 1
print(result)
</code></pre>
<p><strong>输出:</strong></p>
<pre><code>{'Blue': {'dress': 2, 'gloves': 1, 'hat': 1, 'jeans': 1},
'Gold': {'boxers': 1, 'dress': 1, 't-shirt': 1},
'White': {'briefs': 1, 'tanktop': 1}}
</code></pre>