[英]List of lists of tuples, group by first element and add second elements
假设我有以下元组列表列表:
tuples = [
[
('2017-04-11', '2000000.00'),
('2017-04-12', '1000000.00'),
('2017-04-13', '3000000.00')
],
[
('2017-04-12', '472943.00'),
('2017-04-13', '1000000.00')
]
# ...
]
我将如何根据第一个元素(日期)对它们进行分组并添加另一个元素。
例如,我想要这样的东西:
tuples = [('2017-04-11', '2000000.00'), ('2017-04-12', '1472943.00'), ('2017-04-13', '4000000.00')],
使用itertools.chain.from_iterable
、 itertools.groupby
和sum
函数的解决方案:
import itertools, operator
tuples = [
[('2017-04-11', '2000000.00'), ('2017-04-12', '1000000.00'), ('2017-04-13', '3000000.00')],
[('2017-04-12', '472943.00'), ('2017-04-13', '1000000.00')]
]
result = [(k, "%.2f" % sum(float(t[1]) for t in g))
for k,g in itertools.groupby(sorted(itertools.chain.from_iterable(tuples)), operator.itemgetter(0))]
print(result)
输出:
[('2017-04-11', '2000000.00'), ('2017-04-12', '1472943.00'), ('2017-04-13', '4000000.00')]
首先,将元组列表从元组列表中取出,然后使用itertools.groupby
,
import itertools
import operator
lists = [
[('2017-04-11', '2000000.00'), ('2017-04-12', '1000000.00'), ('2017-04-13', '3000000.00')],
[('2017-04-12', '472943.00'), ('2017-04-13', '1000000.00')]
]
# Step 1: Flat a list of tuples out of a list of lists of tuples
list_tuples = [t for sublist in lists for t in sublist]
'''
[('2017-04-11', '2000000.00'), ('2017-04-12', '1000000.00'), ('2017-04-13', '3000000.00'), ('2017-04-12', '472943.00'), ('2017-04-13', '1000000.00')]
'''
# Step 2: Groupby
results = list()
for key, group in itertools.groupby(sorted(list_tuples), operator.itemgetter(0)):
s = sum(float(t[1]) for t in group)
results.append((key, s))
print(results)
#[('2017-04-11', 2000000.0), ('2017-04-12', 1472943.0), ('2017-04-13', 4000000.0)]
我的方法是将嵌套列表转换为平面列表并对其进行迭代:
t = [
[('2017-04-11', '2000000.00'), ('2017-04-12', '1000000.00'), ('2017-04-13', '3000000.00')],
[('2017-04-12', '472943.00'), ('2017-04-13', '1000000.00')]
]
a={}
for i,j in sum(t,[]):
a[i]=a[i]+float(j) if i in a else float(j)
print(a)
输出:
{'2017-04-11': 2000000.0, '2017-04-13': 4000000.0, '2017-04-12': 1472943.0}
如果你想要一个列表,你可以使用[(k,v) for k,v in a.items()])
展平列表,然后使用 defaultdict:
from collections import defaultdict
flattened_tuples = [item for sublist in tuples for item in sublist]
result = defaultdict(float)
for date, value in flattened_tuples:
result[date] += float(value)
print(result)
返回{'2017-04-11': 2000000.0, '2017-04-12': 1472943.0, '2017-04-13': 4000000.0}
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