Numpy Tutorial

Creating NumPy Array

NumPy Array Manipulation

Matrix in NumPy

Operations on NumPy Array

Reshaping NumPy Array

Indexing NumPy Array

Arithmetic operations on NumPy Array

Linear Algebra in NumPy Array

NumPy and Random Data

Sorting and Searching in NumPy Array

Universal Functions

Working With Images

Projects and Applications with NumPy

Stack the sequence of NumPy array horizontally

In NumPy, stacking arrays horizontally means adding arrays column-wise. The function for this purpose is numpy.hstack(). Let's dive into how it's used.

1. Introduction:

The numpy.hstack() function is used to stack arrays in sequence horizontally (i.e., column-wise).

2. Basic Setup:

Installation:

If you haven't installed NumPy yet, you can do so with:

pip install numpy

Importing:

Begin by importing NumPy:

import numpy as np

3. Using the hstack() function:

Basic Horizontal Stacking:

Given two or more arrays, you can stack them horizontally:

arr1 = np.array([[1, 2], 
                 [3, 4]])

arr2 = np.array([[5, 6], 
                 [7, 8]])

stacked_array = np.hstack((arr1, arr2))
print(stacked_array)

Output:

[[1 2 5 6]
 [3 4 7 8]]

Stacking More Than Two Arrays:

You can stack more than two arrays at once:

arr3 = np.array([[9, 10], 
                 [11, 12]])

stacked_array = np.hstack((arr1, arr2, arr3))
print(stacked_array)

Output:

[[ 1  2  5  6  9 10]
 [ 3  4  7  8 11 12]]

Stacking Arrays of Different Dimensions:

If you want to horizontally stack arrays of different dimensions, one option is to use the reshape or column_stack functions to ensure they have matching shapes before stacking:

arr1 = np.array([1, 2, 3])
arr2 = np.array([[4, 5, 6], 
                 [7, 8, 9]])

# Reshape arr1 to match arr2's shape
arr1_reshaped = arr1.reshape(2, -1)

stacked_array = np.hstack((arr1_reshaped, arr2))
print(stacked_array)

Output:

[[1 4 5 6]
 [2 7 8 9]]

Note: In the above example, -1 in reshape automatically calculates the necessary number of columns.

4. Alternative Using concatenate:

You can also use the concatenate function with the axis=1 argument to achieve horizontal stacking:

stacked_array = np.concatenate((arr1, arr2), axis=1)
print(stacked_array)

5. Conclusion:

The hstack() function in NumPy is a handy tool for horizontally stacking arrays. Whether you're working with two arrays or several arrays, it offers an efficient and intuitive way to combine data column-wise. Remember to ensure that the arrays are of compatible shapes for stacking.

1. Horizontal stacking of arrays in NumPy:

Description: Horizontal stacking of arrays in NumPy refers to concatenating arrays side by side along a specified axis.

Code:

import numpy as np

# Create two 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Horizontal stack the arrays
stacked_array = np.hstack((array1, array2))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Horizontally Stacked Array:")
print(stacked_array)

2. Concatenate arrays side by side with NumPy:

Description: Concatenating arrays side by side in NumPy can be achieved using functions like numpy.hstack.

Code:

import numpy as np

# Create two 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Concatenate arrays horizontally
concatenated_array = np.hstack((array1, array2))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Concatenated Array:")
print(concatenated_array)

3. Python NumPy hstack function examples:

Description: The numpy.hstack function in Python NumPy is specifically designed for horizontally stacking arrays.

Code:

import numpy as np

# Create two 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Use hstack to horizontally stack arrays
stacked_array = np.hstack((array1, array2))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Horizontally Stacked Array:")
print(stacked_array)

4. Stacking arrays along columns in NumPy:

Description: Stacking arrays along columns in NumPy can be done using functions like numpy.hstack for 1D arrays or numpy.column_stack for 2D arrays.

Code:

import numpy as np

# Create two 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Stack arrays along columns
stacked_array = np.column_stack((array1, array2))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Stacked Array Along Columns:")
print(stacked_array)

5. Horizontally combining NumPy arrays in Python:

Description: Horizontally combining NumPy arrays in Python can be achieved using functions like numpy.hstack or numpy.column_stack.

Code:

import numpy as np

# Create two 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Combine arrays horizontally
combined_array = np.hstack((array1, array2))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Horizontally Combined Array:")
print(combined_array)

6. NumPy horizontal concatenation along axis 1:

Description: NumPy horizontal concatenation along axis 1 is achieved using functions like numpy.hstack or numpy.concatenate with the appropriate axis parameter.

Code:

import numpy as np

# Create two 2D NumPy arrays
array1 = np.array([[1, 2],
                   [3, 4]])
array2 = np.array([[5, 6],
                   [7, 8]])

# Horizontal concatenation along axis 1
concatenated_array = np.concatenate((array1, array2), axis=1)

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Horizontal Concatenation along Axis 1:")
print(concatenated_array)

7. Concatenating multiple arrays horizontally in NumPy:

Description: Concatenating multiple arrays horizontally in NumPy can be done using functions like numpy.hstack or numpy.concatenate.

Code:

import numpy as np

# Create three 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])
array3 = np.array([7, 8, 9])

# Concatenate multiple arrays horizontally
concatenated_array = np.hstack((array1, array2, array3))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Array 3:")
print(array3)
print("Concatenated Array:")
print(concatenated_array)

8. Efficient ways to stack arrays side by side in NumPy:

Description: Efficient ways to stack arrays side by side in NumPy involve using functions like numpy.hstack or numpy.column_stack for 1D arrays, and numpy.concatenate for 2D arrays.

Code:

import numpy as np

# Create two 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Efficiently stack arrays side by side
stacked_array = np.hstack((array1, array2))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Stacked Array:")
print(stacked_array)

9. Joining arrays horizontally using NumPy:

Description: Joining arrays horizontally using NumPy can be achieved using functions like numpy.hstack for 1D arrays or numpy.concatenate for 2D arrays.

Code:

import numpy as np

# Create two 1D NumPy arrays
array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Join arrays horizontally
joined_array = np.hstack((array1, array2))

print("Array 1:")
print(array1)
print("Array 2:")
print(array2)
print("Joined Array Horizontally:")
print(joined_array)
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