Matlab到Python转换二进制文件读取 [英] Matlab to Python Conversion binary file read

问题描述

我是Matlab和Python的新手，我必须将Matlab中的程序转换为Python.我不确定在Python中从文件读取后如何转换数据.使用的文件是二进制文件.

I am new to both Matlab and Python and I have to convert a program in Matlab to Python. I am not sure how to typecast the data after reading from the file in Python. The file used is a binary file.

下面是Matlab代码:

Below is the Matlab code:

fid = fopen (filename, 'r');
 fseek (fid, 0, -1);
 meta = zeros (n, 9, 'single');
 v = zeros (n, 128, 'single');
 d = 0;
 for i = 1:n
   meta(i,:) = fread (fid, 9, 'float');
   d = fread (fid, 1, 'int');
   v(i,:) = fread (fid, d, 'uint8=>single');
 end

我已经用python编写了以下程序:

I have written the below program in python:

fid = open(filename, 'r')
fid.seek(0 , 0)
meta = np.zeros((n,9),dtype = np.float32)
v = np.zeros((n,128),dtype = np.float32)

for i in range(n):
  data_str = fid.read(9);
  meta[1,:] = unpack('f', data_str)

对于此解包，我得到的错误为

For this unpack, I getting the error as

解压缩需要长度为4的字符串参数"

"unpack requires a string argument of length 4"

. 请提出建议以使其正常工作.

. Please suggest someway to make it work.

推荐答案

我在这个问题上看了一些，主要是因为在不久的将来我也需要这个.事实证明，有一个使用numpy的非常简单的解决方案，假设您像我一样存储了一个matlab矩阵.

I looked a little in the problem mainly because I need this in the near future, too. Turns out there is a very simple solution using numpy, assuming you have a matlab matrix stored like I do.

import numpy as np

def read_matrix(file_name):
    return np.fromfile(file_name, dtype='<f')  # little-endian single precision float

arr = read_matrix(file_path)

print arr[0:10]  #sample data
print len(arr)  # number of elements

您必须了解自己的数据类型(dtype).有关帮助，请此处.我使用fwrite(fid,value,'single');将数据存储在matlab中，如果您有相同的数据，则上面的代码将起作用. 注意，返回的变量是一个列表.您必须将其格式化以匹配数据的原始形状，在我的情况下，len(arr)来自大小为15360 x 20的矩阵为307200.

The data type (dtype) you must find out yourself. Help on this is here. I used fwrite(fid,value,'single'); to store the data in matlab, if you have the same, the code above will work. Note, that the returned variable is a list; you'll have to format it to match the original shape of your data, in my case len(arr) is 307200 from a matrix of the size 15360 x 20.

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