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The program or internal processor interprets the binary file. It contains bytes as content. When we read a binary file, an bytesobject of type is returned.

open()Read a binary file using the function in Python

In Python, we have open()the openFile function, which is used to create a file object. Pass the path of the file to the function and open the file in a specific mode, which is read mode by default. When we open a binary file, we have to specify bthe openFile parameter while opening such a file in read, write or append mode. In this tutorial, we will deal with the binary read mode - READ_MODE rb.

In the following code, we will read a binary file and print a character from the file.

with open("sample.bin", "rb") as f:
    data = f.read()

print(data[2])

Output:

83

If we print the individual characters then we can look at the integers.

Python has a structpackage called that has many methods for working with binary data stored in files, databases, and more.

struct.unpack()Used to read packed data in a specified format layout. This layout is used when packing and unpacking data and is specified using format characters. These format characters and their sizes are shown below.

Note that struct.unpack()functions always return a tuple.

import struct

with open("sample.bin", "rb") as f:
    data = f.read()

unpack_result = struct.unpack("hhl", data[0:8])
print(unpack_result)

Output:

(1280, 27731, 7037801)

Here, hhlshort, short, long int is represented as the data format layout, which we can see in the output. That is why the unpacked buffer is only 8 bytes, because the size of the format layout is 8 (2+2+4).

pathlib.PathReading binary files with Python

We can also use the method in the class pathlibin the library to read the file in byte mode and then interpret the data using the function as described earlier.Pathread_bytes()struct.unpack()

from pathlib import Path
import struct

data = Path("sample.bin").read_bytes()

multiple = struct.unpack("ii", data[:8])

print(multiple)

Output:

(1817380096, 7037801)

numpy.fromfile()Read a binary file using the function in Python

NumPyThere is another interesting method provided in the module. Using fromfile()the function in this module, we can dtype()read binary data from a file after specifying the format data using the function. This is considered as a fast method. The following code shows how to implement this functionality.

import numpy as np

with open("sample.bin") as f:
    rectype = np.dtype(np.int32)
    bdata = np.fromfile(f, dtype=rectype)

print(bdata)

Output:

[1817380096    7037801]

Here, we specify the format type as a 32-bit integer and use fromfile()the function to extract the data.