将numpy数组转换为给定格式的字符串

Question

I would like to convert a numpy array into a string representation with a given format. This

from io import BytesIO
import numpy

data = numpy.random.rand(5)

s = BytesIO()
numpy.savetxt(s, data, "%.15e")
out = s.getvalue().decode()

print(out)

3.208726298090422e-01
6.817590490300521e-01
3.446035342640975e-01
7.871066165361260e-01
4.829308426574872e-01

works, but savetxt is slow. tofile is about twice as fast, but I don't know how to get it to work with BytesIO . Perhaps there is another alternative.

Any hints?

Answer 1

You can do something like this:

import numpy as np

data = np.random.rand(5)
out ='\n'.join(map('{:.15e}'.format, data))
print(out)

Output example:

2.599889521964338e-02
8.936410392960248e-01
7.074905121425787e-01
4.318334519811902e-01
8.219700656108224e-01