What is the equivalent of 'fread' from Matlab in Python?

Question

I have practically no knowledge of Matlab, and need to translate some parsing routines into Python. They are for large files, that are themselves divided into 'blocks', and I'm having difficulty right from the off with the checksum at the top of the file. What exactly is going on here in Matlab? ``` status = fseek(fid, 0, 'cof'); fposition = ftell(fid); disp(' '); disp(['** Block ',num2str(iBlock),' File Position = ',int2str(fposition)]); % ----------------- Block Start ------------------ % [A, count] = fread(fid, 3, 'uint32'); if(count == 3) magic_l = A(1); magic_h = A(2); block_length = A(3); else if(fposition == file_length) disp(['** End of file OK']); else disp(['** Cannot read block start magic ! Note File Length = ',num2str(file_length)]); end ok = 0; break; end ``` fid is the file currently being looked at iBlock is a counter for which 'block' you're in within the file magic_l and magic_h are to do with checksums later, here is the code for that (follows straight from the code…

Accepted Answer

From the documentation of `fread`, it is a function to read binary data. The second argument specifies the size of the output vector, the third one the size/type of the items read.

In order to recreate this in Python, you can use the `array` module:

```
f = open(...)
import array
a = array.array("L")  # L is the typecode for uint32
a.fromfile(f, 3)
```

This will read read three uint32 values from the file `f`, which are available in `a` afterwards. From the documentation of `fromfile`:

Read n items (as machine values) from the file object f and append them to the end of the array. If less than n items are available, EOFError is raised, but the items that were available are still inserted into the array. f must be a real built-in file object; something else with a read() method won’t do.

Arrays implement the sequence protocol and therefore support the same operations as lists, but you can also use the `.tolist()` method to create a normal list from the array.

What is the equivalent of 'fread' from Matlab in Python?

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