pythonnwise numpy数组迭代
是否有一个numpy函数可以有效地允许迭代pythonnwise numpy数组迭代,python,numpy,Python,Numpy,是否有一个numpy函数可以有效地允许迭代 # http://seriously.dontusethiscode.com/2013/04/28/nwise.html from itertools import tee, islice nwise = lambda xs, n=2: zip(*(islice(xs, idx, None) for idx, xs in enumerate(tee(xs, n)))) 将平均数应用于元素nwise?要获得移动平均线?通用: import numpy
# http://seriously.dontusethiscode.com/2013/04/28/nwise.html
from itertools import tee, islice
nwise = lambda xs, n=2: zip(*(islice(xs, idx, None) for idx, xs in enumerate(tee(xs, n))))
将平均数应用于元素nwise?要获得移动平均线?通用:
import numpy as np
from numpy.lib.stride_tricks import as_strided
def moving_slice(a, k):
a = a.ravel()
return as_strided(a, (a.size - k + 1, k), 2 * a.strides)
移动平均值更好:
def moving_avg(a, k):
ps = np.cumsum(a)
return (ps[k-1:] - np.r_[0, ps[:-k]]) / k
例如:
a = np.arange(10)
moving_avg(a, 4)
# array([ 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, 7.5])
ms = moving_slice(a, 4)
ms
# array([[0, 1, 2, 3],
# [1, 2, 3, 4],
# [2, 3, 4, 5],
# [3, 4, 5, 6],
# [4, 5, 6, 7],
# [5, 6, 7, 8],
# [6, 7, 8, 9]])
# no data are copied:
a[4] = 0
ms
# array([[0, 1, 2, 3],
# [1, 2, 3, 0],
# [2, 3, 0, 5],
# [3, 0, 5, 6],
# [0, 5, 6, 7],
# [5, 6, 7, 8],
# [6, 7, 8, 9]])
很好,请给我一点时间,让我看看这些…:)非常感谢你的回答!它非常聪明