高效的解决方案

卷积比直接的方法好得多，但(我猜)它使用FFT，因此相当慢。但是，下面的方法特别适用于计算运行平均值

def running_mean(x, N):
    cumsum = numpy.cumsum(numpy.insert(x, 0, 0)) 
    return (cumsum[N:] - cumsum[:-N]) / float(N)

要检查的代码

In[3]: x = numpy.random.random(100000)
In[4]: N = 1000
In[5]: %timeit result1 = numpy.convolve(x, numpy.ones((N,))/N, mode='valid')
10 loops, best of 3: 41.4 ms per loop
In[6]: %timeit result2 = running_mean(x, N)
1000 loops, best of 3: 1.04 ms per loop

注意numpy。allclose(result1, result2)为True，两个方法等价。 N越大，时间差异越大。

警告:虽然cumsum更快，但会增加浮点错误，这可能导致您的结果无效/不正确/不可接受

这里的评论指出了这个浮点错误问题，但我在回答中让它更明显。

# demonstrate loss of precision with only 100,000 points
np.random.seed(42)
x = np.random.randn(100000)+1e6
y1 = running_mean_convolve(x, 10)
y2 = running_mean_cumsum(x, 10)
assert np.allclose(y1, y2, rtol=1e-12, atol=0)

the more points you accumulate over the greater the floating point error (so 1e5 points is noticable, 1e6 points is more significant, more than 1e6 and you may want to resetting the accumulators) you can cheat by using np.longdouble but your floating point error still will get significant for relatively large number of points (around >1e5 but depends on your data) you can plot the error and see it increasing relatively fast the convolve solution is slower but does not have this floating point loss of precision the uniform_filter1d solution is faster than this cumsum solution AND does not have this floating point loss of precision

如果你选择自己生成，而不是使用现有的库，请注意浮点错误并尽量减少其影响:

class SumAccumulator:
    def __init__(self):
        self.values = [0]
        self.count = 0

    def add( self, val ):
        self.values.append( val )
        self.count = self.count + 1
        i = self.count
        while i & 0x01:
            i = i >> 1
            v0 = self.values.pop()
            v1 = self.values.pop()
            self.values.append( v0 + v1 )

    def get_total(self):
        return sum( reversed(self.values) )

    def get_size( self ):
        return self.count

如果所有的值都是大致相同的数量级，那么这将通过始终添加大致相似的数量级值来帮助保持精度。

使用@Aikude的变量，我编写了一行程序。

import numpy as np

mylist = [1, 2, 3, 4, 5, 6, 7]
N = 3

mean = [np.mean(mylist[x:x+N]) for x in range(len(mylist)-N+1)]
print(mean)

>>> [2.0, 3.0, 4.0, 5.0, 6.0]

如果你必须为非常小的数组(少于200个元素)重复这样做，我发现只用线性代数就能得到最快的结果。 最慢的部分是建立你的乘法矩阵y，你只需要做一次，但之后可能会更快。

import numpy as np
import random 

N = 100      # window size
size =200     # array length

x = np.random.random(size)
y = np.eye(size, dtype=float)

# prepare matrix
for i in range(size):
  y[i,i:i+N] = 1./N
  
# calculate running mean
z = np.inner(x,y.T)[N-1:]

比起numpy或scipy，我建议熊猫们更快地做到这一点:

df['data'].rolling(3).mean()

这取列“数据”的3个周期的移动平均值(MA)。你也可以计算移位的版本，例如排除当前单元格的版本(向后移位一个)可以很容易地计算为:

df['data'].shift(periods=1).rolling(3).mean()

我还没有检查这有多快，但你可以试试:

from collections import deque

cache = deque() # keep track of seen values
n = 10          # window size
A = xrange(100) # some dummy iterable
cum_sum = 0     # initialize cumulative sum

for t, val in enumerate(A, 1):
    cache.append(val)
    cum_sum += val
    if t < n:
        avg = cum_sum / float(t)
    else:                           # if window is saturated,
        cum_sum -= cache.popleft()  # subtract oldest value
        avg = cum_sum / float(n)