您无法获得线性时间,但可以更快地完成。对我来说,这看起来像是一个矩阵乘法,所以我建议您使用numpy
:
import numpy as np
keys = ['key1', 'key2', 'key3']
values = np.matrix([
[1.1, 1.2, 1.3, 1.4],
[2.1, 2.2, 2.3, 2.4],
[3.1, 3.2, 3.3, 3.4]
])
weights = np.matrix([[10., 20., 30., 40.]]).transpose()
res = (values * weights).transpose().tolist()[0]
items = zip(res, keys)
items.sort(reverse=True)
这使
[(330.0, 'key3'), (230.0, 'key2'), (130.0, 'key1')]
有感谢@Ondro为np.dot并以@unutbu为np.argsort,这里是numpy的完全的改进版本:
import numpy as np
# set up values
keys = np.array(['key1', 'key2', 'key3'])
values = np.array([
[1.1, 1.2, 1.3, 1.4], # values1_x
[2.1, 2.2, 2.3, 2.4], # values2_x
[3.1, 3.2, 3.3, 3.4] # values3_x
])
weights = np.array([10., 20., 30., 40.])
# crunch the numbers
res = np.dot(values, -weights) # negative of weights!
order = res.argsort(axis=0) # sorting on negative value gives
# same order as reverse-sort; there does
# not seem to be any way to reverse-sort
# directly
sortedkeys = keys[order].tolist()
结果是['key3', 'key2', 'key1']
。