怎么能把：
{'mitsuwa': [['rice']],
'99ranch': [['msg'], ['sambal', 'banana leaf']],
'costco': [['eggs']]}
改成：
{'mitsuwa': ['rice'], '99ranch': ['msg', 'sambal', 'banana leaf'], \
'costco': ['eggs']}
我的代码：
def grocery_summary(grocery_purchases):
"""
I create an empty dictionary, then use setdefault to append keys and values.
>>> p1 = [{'mitsuwa': ['rice'], '99ranch': ['msg']}, \
{'99ranch': ['sambal', 'banana leaf'], 'costco': ['eggs']}]
>>> grocery_summary(p1)
{'mitsuwa': ['rice'], '99ranch': ['msg', 'sambal', 'banana leaf'], \
'costco': ['eggs']}
>>> p2 = [{'ralphs': ['milk', 'carrot', 'milk'], 'costco': ['carrot']}, \
{'ralphs': ['carrot', 'carrot', 'milk'], 'costco': ['carrot']}]
>>> grocery_summary(p2)
{'ralphs': ['milk', 'carrot'], 'costco': ['carrot']}
# Add at least 3 doctests below here #
"""
# YOUR CODE GOES HERE #
keys=[]
values=[]
for i in grocery_purchases:
for e in i:
keys.append(e)
values.append(i[e])
dic = {}
for k in range(len(keys)):
if keys[k] not in dic:
dic[keys[k]]=[values[k]]
elif keys[k] in dic:
dic[keys[k]].append(values[k])
return dic
Append()用加法代替就好了：
def grocery_summary(grocery_purchases):
"""
I create an empty dictionary, then use setdefault to append keys and values.
>>> p1 = [{'mitsuwa': ['rice'], '99ranch': ['msg']}, \
{'99ranch': ['sambal', 'banana leaf'], 'costco': ['eggs']}]
>>> grocery_summary(p1)
{'mitsuwa': ['rice'], '99ranch': ['msg', 'sambal', 'banana leaf'], \
'costco': ['eggs']}
>>> p2 = [{'ralphs': ['milk', 'carrot', 'milk'], 'costco': ['carrot']}, \
{'ralphs': ['carrot', 'carrot', 'milk'], 'costco': ['carrot']}]
>>> grocery_summary(p2)
{'ralphs': ['milk', 'carrot'], 'costco': ['carrot']}
# Add at least 3 doctests below here #
"""
# YOUR CODE GOES HERE #
keys=[]
values=[]
for i in grocery_purchases:
for e in i:
keys.append(e)
values.append(i[e])
dic = {}
for k in range(len(keys)):
if keys[k] not in dic:
dic[keys[k]]=values[k]
elif keys[k] in dic:
dic[keys[k]]=dic[keys[k]]+values[k]
return dic