问题描述
我想将Python浮点数转换为字节数组，将其编码为32位小尾数IEEE浮点数，以便将其写入二进制文件.
I want to convert a Python float into a byte array, encoding it as a 32 bit little-endian IEEE floating point number, in order to write it to a binary file.
在Python 3中执行此操作的现代Pythonic方法是什么?对于整数，我可以执行 my_int.to_bytes(4，'little')，但是没有用于浮点数的 to_bytes 方法.
What is the modern Pythonic way to do that in Python 3? For ints I can do my_int.to_bytes(4,'little'), but there is no to_bytes method for floats.
如果我可以一次为numpy数组中的每个浮点数(使用dtype numpy.float32)做到这一点，那就更好了.但是请注意，我需要将其作为字节数组获取，而不仅仅是立即将数组写入文件中.
It's even better if I can do this in one shot for every float in a numpy array (with dtype numpy.float32). But note that I need to get it as a byte array, not just write the array to a file immediately.
有一些听起来相似的问题，但它们似乎主要是关于获取十六进制数字，而不是写入二进制文件.
There are some similar-sounding questions, but they seem mostly to be about getting the hex digits, not writing to a binary file.
推荐答案
使用正确的 dtype ，您可以将数组的数据缓冲区写入字节串或二进制文件:
With the right dtype you can write the array's data buffer to a bytestring or to a binary file:
In [449]: x = np.arange(4., dtype='<f4')
In [450]: x
Out[450]: array([0., 1., 2., 3.], dtype=float32)
In [451]: txt = x.tostring()
In [452]: txt
Out[452]: b'\x00\x00\x00\x00\x00\x00\x80?\x00\x00\x00@\x00\x00@@'
In [453]: x.tofile('test')
In [455]: np.fromfile('test','<f4')
Out[455]: array([0., 1., 2., 3.], dtype=float32)
In [459]: with open('test','br') as f: print(f.read())
b'\x00\x00\x00\x00\x00\x00\x80?\x00\x00\x00@\x00\x00@@'
更改结尾:
In [460]: x.astype('>f4').tostring()
Out[460]: b'\x00\x00\x00\x00?\x80\x00\x00@\x00\x00\x00@@\x00\x00'
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