Question

我在spyder IDE中运行了以下代码：

idnum = 201034628
seed(idnum);
w = np.random.rand(200)
print(w)

这将产生以下结果：

[0.00176212 0.79092217 0.1759531  0.00239256 0.78842458 0.30404404
 0.25633004 0.88271124 0.72031936 0.17356416 0.5674158  0.83897948
 0.4133943  0.22471237 0.66562002 0.70207085 0.55722598 0.86308392
 0.14584968 0.66224337 0.79900625 0.2687224  0.45508786 0.99014178
 0.176943   0.42335567 0.41034833 0.75497287 0.41301282 0.11294302
 0.58715198 0.01524138 0.58633177 0.9784454  0.14610789 0.68654175
 0.94733177 0.93776749 0.17294272 0.7491281  0.94087871 0.60510781
 0.43708462 0.77303273 0.13250525 0.50794632 0.36706808 0.46873059
 0.99757662 0.144249   0.69427544 0.78359245 0.64836852 0.16574067
 0.98633778 0.05613428 0.51713291 0.27246708 0.26216551 0.44605373
 0.99963659 0.90569603 0.31139955 0.25559081 0.8295379  0.84638476
 0.48194161 0.505123   0.57456517 0.62727722 0.11940848 0.49435157
 0.07438197 0.11481526 0.74184931 0.94697125 0.93788422 0.3586455
 0.852594   0.35167897 0.57139446 0.77923007 0.09070311 0.07821641
 0.38140649 0.80945136 0.81820638 0.8140444  0.94458644 0.42983398
 0.06609377 0.25737315 0.27873234 0.87183073 0.14317078 0.8964766
 0.00731705 0.16095917 0.70980283 0.49757526 0.06990482 0.15304861
 0.02710815 0.21319381 0.82069776 0.19839614 0.64250566 0.6383788
 0.12539173 0.74583486 0.11041236 0.827742   0.20340574 0.03643315
 0.62638826 0.12454928 0.64567226 0.04782684 0.88455847 0.62114705
 0.82253557 0.12590787 0.99624612 0.0780055  0.38312778 0.56969024
 0.21771078 0.18022973 0.06825607 0.05189065 0.19410785 0.93458232
 0.84006441 0.8796388  0.00574523 0.92213916 0.60108549 0.48774697
 0.79918579 0.05700109 0.42167703 0.26358089 0.37023659 0.05556867
 0.1788227  0.63840475 0.79772203 0.20969062 0.55459356 0.81425831
 0.06324903 0.274849   0.15092814 0.65504038 0.57138257 0.37113864
 0.84318386 0.58306703 0.95677286 0.28962055 0.31085227 0.92607168
 0.61132872 0.42862182 0.67385059 0.58591843 0.98309858 0.12926512
 0.89650825 0.47853266 0.16842571 0.77785123 0.16004964 0.24379739
 0.76415568 0.14338659 0.73812864 0.52921474 0.8678008  0.82205399
 0.1219327  0.83831355 0.5219863  0.67680272 0.05486754 0.89255115
 0.91609614 0.74104108 0.98763434 0.07343619 0.0879543  0.55360531
 0.01048341 0.01083459 0.13080064 0.51212431 0.24552376 0.77620793
 0.16560353 0.42042389]

我需要从w数组中的数字中找到最小4个值的平均值。我该怎么办？

Answer 1

您可以使用heapq.nsmallest，它应该比排序要快一点：

import heapq
import statistics

print(statistics.mean(heapq.nsmallest(4, w)))

Answer 2

您可以简单地做到：

sum(sorted(w)[:4])/len(sorted(w)[:4])

Answer 3

尝试对数组进行排序，并通过切片选择4个最小值，然后求平均值。

np.mean(np.sort(w)[:4])

Answer 4

将numpy.partition与kth=3一起使用，然后取前四个值的平均值：

In [41]: np.partition(w, 3)[:4].mean()
Out[41]: 0.004304237929249388

在产生200个随机数的数组中查找最小4个值的平均值

4 个答案: