如何将16位PCM数据转换为python中的float？

Question

I'm new to python and Raspberry pi. I'm involved in a project, where I have to embed a bit stream to a wav file. At first I opened the wav file and it is a 2 channel, 16 bit wav file. In order to change the sample values I should convert these sample values into float. I tried a code. But when I run the module, it gives errors as "name struct" isn't defined. And also here I have tried to convert data into integers, since i don't know how to convert into float.If someone can help me to correct this program or suggest another code, then it will be a great help. Thank you.

from struct import unpack
import numpy as np
import wave

wavfile = wave.open('/home/pi/desktop/codes/mysong.wav','r')
number_of_frames = wavfile.getnframes()
no_channels = wavfile.getnchannels()
raw_data = wavfile.readframes(number_of_frames)

total_samples = number_of_frames * no_channels
fmt = "%ih" % total_samples
integer_data = struct.unpack(fmt,raw_data)

Answer 1

As @jonrsharpe said, you either :

# if using from ... import ...
from struct import unpack
...
# then change this to
integer_data = unpack(fmt,raw_data)

...

# if using import ...
import struct
...
# then this will work fine
integer_data = struct.unpack(fmt,raw_data)

But do not mix & match the imports together.