python - 如何使用字典理解计算键子字符串匹配的字典值小计

Question

我想将下面的字典逻辑转换为字典理解逻辑，我该怎么做？

# Example: You have this dictA as input 
dictA = {'chiken_biryani': 350, 'chiken_chilli': 300, 'motton_fry': 350, 'motton_biryani': 400, 'fish_prowns_fry': 250, 'fish_dry':300}

# Q: Print the total of each category, chiken, motton and fish items sub total values, using dictionary comprehension?
# Expected Output: {'chicken': 650, 'motton': 750, 'fish': 550}
dictB = dict()

for (k,v) in dictA.items():
    k = k.split('_')[0]
    if dictB.get(k) is None:
        dictB[k] = v
    else:
        dictB[k] = dictB.get(k)+v

print(dictB)

输出：

{'chiken': 650, 'motton': 750, 'fish': 550}

标签： pythonpython-3.xdictionarydictionary-comprehension

Answer 1

为什么要使用 dict comp？这是可行的，但它会很丑。

我会用一个defaultdict

from collections import defaultdict

dict_b = defaultdict(int)

for k, v in dict_a.items():
    dict_b[k.split('_')[0]] += v