Python:如何查找重复项并将其值相加？

Question

[('Visa', 980.5), ('Rogers', 61.5), ('Visa', 215.0)]

例如,我有上面的元组列表,我如何找到重复项(即'Visa')并将它们的值相加(即980.5 + 215.0)？输出应该是:

[('Visa', 1195.5), ('Rogers', 61.5)]

Answer 1

使用字典:

>>> data = [('Visa', 980.5), ('Rogers', 61.5), ('Visa', 215.0)]
>>> result = {}
>>> for card,value in data:
        total = result.get(card,0) + value
        result[card] = total


>>> print result.items()
[('Visa': 1195.5), ('Rogers': 61.5)]

Answer 2

看起来每个人都忘记了Collections.Counter：

from collections import Counter


c = Counter()
for card, val in lst:
    c[card] += val
print(list(c.items()))

# [('Visa', 1195.5), ('Rogers', 61.5)]