python中具有相同代码的sum list对象值

没错,用 groupby 和 sum comprehensions : 正如评论中所说,使用groupby列表需要预先排序。 此外,您还可以使用 operator.attrgetter 而不是 key sorted 和 .

l = [  
    {  
        'balance':-32399.0,
        'code':u'1011',
        'name':u'Stock Valuation Account'
    },
    ...
]

from itertools import groupby
import operator 

selector_func = operator.attrgetter("code")
l = sorted(l, key=selector_func)
result = [{"code" : code, "balance" : sum(x["balance"] for x in values)} for code, values in groupby(l, selector_func)]
print(result)

结果:

[{'code': '1011', 'balance': -57978.0900005}, {'code': '1101', 'balance': -3550000.0}]

live example

这是一个没有任何导入的oneliner:

a = ...
result = [{'balance' : sum([i['balance'] for i in a if i['code']==j]), 'code' : j} for j in set([k['code'] for k in a])]

输出

[{'balance': -3550000.0, 'code': '1101'}, {'balance': -57978.0900005, 'code': '1011'}]

data = [
    {
        'balance':-32399.0,
        'code':u'1011',
        'name':u'Stock Valuation Account'
    },
    ...
]
d = {}
for entry in data:
    d[entry['code']] = d.get(entry['code'],0) + entry['balance']
print([{'balance':b,'code':c} for c,b in d.items()])

将打印:

[{'balance': -57978.0900005, 'code': '1011'}, {'balance': -3550000.0, 'code': '1101'}]