Np.unit8 In Python

In this Python tutorial, I will explain the np.unit8 in Python data type in detail, including its characteristics, uses, and how it compares to other data types.

The np.unit8 in Python data type is an unsigned 8-bit integer type used in the NumPy library, capable of representing values from 0 to 255. It’s highly efficient for memory-sensitive applications due to its compact size. Commonly used in image processing, numpy.uint8 is ideal for handling arrays of pixel values and for data storage where values fall within its range, ensuring efficient use of memory while processing large datasets.

Table of Contents

NumPy, a fundamental package for scientific computing in Python, offers a variety of data types for different kinds of numerical data. Among these is numpy.uint8, an unsigned 8-bit integer type.

uint8 in Python Characteristics

Unsigned Integer: numpy.uint8 represents an unsigned 8-bit integer. Being unsigned means it can only represent non-negative values.
Value Range: It can represent values from 0 to 255. This is because 8 bits can represent 2⁸ values, and without negative numbers, this range is 0 to 255.
Memory Efficiency: Using only 8 bits, it’s a compact data type, which makes it memory efficient for storing large arrays of data where the values fall within its range.

Python uint8 type uses

Image Processing: It’s extensively used in image processing as images are often represented in the form of arrays, with pixel values typically ranging from 0 (black) to 255 (white) for grayscale images.
Data Storage and Handling: In scenarios where data values are known to be within the 0-255 range, using np.unit8 in Python can save memory, which is particularly beneficial for handling large datasets.

uint8 in Python Comparison with Other NumPy Data Types

Against numpy.int8: The np.int8 type is a signed 8-bit integer, ranging from -128 to 127. np.unit8 in Python is often preferred when negative values are not required, as it offers a wider range of positive values.
Against Larger Integer Types: Larger types like numpy.int16, numpy.int32, etc., offer wider ranges but at the cost of increased memory usage. np.unit8 in Python is preferable when its range suffices and memory efficiency is a priority.

uint8 data type Python

Let’s see some examples of how numpy.uint8 is used in Python:

Example 1: Creating a Python uint8 Array in NumPy

import numpy as np
array_uint8 = np.array([0, 128, 255], dtype=np.uint8)
print(array_uint8)
print(type(array_uint8[1]))

Output: Here, we use the dtype parameter in the array() function to assign the values in that data type.

After the creation of the array, we also check the type of the values to confirm whether they are assigned to the correct data type using the type() function.

[  0 128 255]
<class 'numpy.uint8'>

This way we can create an array with np.unit8 in Python.

Example 2: uint8 Python data type used in image processing

from PIL import Image
import numpy as np

# Loading an image and converting it to a numpy array
img = Image.open("C:/Users/kumar/OneDrive/Desktop/Pythonguides_image.jpg")
img_array = np.array(img, dtype=np.uint8)

print(img_array)
print(type(img_array[1]))

Output: The implementation of the code is given below:

[[[255 255 255]
  [255 255 255]
  [255 255 255]
  ...
  [255 255 255]
  [255 255 255]
  [255 255 255]]

 [[255 255 255]
  [255 255 255]
  [255 255 255]
  ...
  [255 255 255]
  [255 255 255]
  [255 255 255]]

 [[255 255 255]
  [255 255 255]
  [255 255 255]
  ...
  [255 255 255]
  [255 255 255]
  [255 255 255]]

 ...

 [[251 251 251]
  [251 251 251]
  [251 251 251]
  ...
  [251 251 251]
  [251 251 251]
  [251 251 251]]

 [[251 251 251]
  [251 251 251]
  [251 251 251]
  ...
  [251 251 251]
  [251 251 251]
  [251 251 251]]

 [[251 251 251]
  [251 251 251]
  [251 251 251]
  ...
  [251 251 251]
  [251 251 251]
  [251 251 251]]]
<class 'numpy.ndarray'>

This way we can use np.unit8 in Python to process images.

Example 3: np.uint8 Python for memory efficiency demonstration

import numpy as np

large_array_uint8 = np.zeros((1000, 1000), dtype=np.uint8)
large_array_int32 = np.zeros((1000, 1000), dtype=np.int32)

print(large_array_uint8.nbytes)
print(large_array_int32.nbytes)

Output: The implementation of the code is mentioned below:

1000000
4000000

This way we can use np.uint8 in Python for memory efficiency demonstration.

Conclusion

The np.uint8 in Python is an essential data type in NumPy, especially beneficial for applications that require memory efficiency and operate within its value range, such as image processing. Its simplicity and efficiency make it a popular choice for Python developers in various data analysis and scientific computing.