python - 如何在 Python 中将一系列浮点值合并到直方图中？

Question

我有一组浮点值(总是小于 0)。我想将其放入直方图中，IE。直方图中的每个条包含值范围 [0,0.150)

我的数据是这样的:

0.000
0.005
0.124
0.000
0.004
0.000
0.111
0.112

使用下面的代码，我希望得到如下所示的结果

[0, 0.005) 5
[0.005, 0.011) 0
...etc.. 

我尝试用我的这段代码进行这样的装箱。但这似乎不起作用。正确的做法是什么？

#! /usr/bin/env python


import fileinput, math

log2 = math.log(2)

def getBin(x):
    return int(math.log(x+1)/log2)

diffCounts = [0] * 5

for line in fileinput.input():
    words = line.split()
    diff = float(words[0]) * 1000;

    diffCounts[ str(getBin(diff)) ] += 1

maxdiff = [i for i, c in enumerate(diffCounts) if c > 0][-1]
print maxdiff
maxBin = max(maxdiff)


for i in range(maxBin+1):
     lo = 2**i - 1
     hi = 2**(i+1) - 1
     binStr = '[' + str(lo) + ',' + str(hi) + ')'
     print binStr + '\t' + '\t'.join(map(str, (diffCounts[i])))

~

Answer 1

如果可能，不要重新发明轮子。 NumPy 拥有您需要的一切:

#!/usr/bin/env python
import numpy as np

a = np.fromfile(open('file', 'r'), sep='\n')
# [ 0.     0.005  0.124  0.     0.004  0.     0.111  0.112]

# You can set arbitrary bin edges:
bins = [0, 0.150]
hist, bin_edges = np.histogram(a, bins=bins)
# hist: [8]
# bin_edges: [ 0.    0.15]

# Or, if bin is an integer, you can set the number of bins:
bins = 4
hist, bin_edges = np.histogram(a, bins=bins)
# hist: [5 0 0 3]
# bin_edges: [ 0.     0.031  0.062  0.093  0.124]