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 vertically

Stacking arrays vertically refers to the operation of adding arrays on top of each other, row-wise. This tutorial will guide you through vertically stacking NumPy arrays using the vstack function and the more general-purpose concatenate function.

1. Setup:

Begin by importing the necessary library:

import numpy as np

2. Understanding Vertical Stacking:

When you stack arrays vertically, you essentially add them on top of each other. For 2D arrays (matrices), this would mean that the resulting array has more rows. The condition is that the arrays being stacked must have the same number of columns.

3. Using vstack:

The vstack function provides a straightforward way to vertically stack arrays.

Example:

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

array2 = np.array([[7, 8, 9],
                   [10, 11, 12]])

# Stack arrays vertically
stacked_array = np.vstack((array1, array2))

print(stacked_array)

Output:

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

4. Using concatenate with axis Argument:

The concatenate function is a general-purpose function for concatenating arrays. For vertical stacking, you'll use the axis=0 argument.

Example:

# Stack arrays vertically using concatenate
stacked_array = np.concatenate((array1, array2), axis=0)

print(stacked_array)

The output is the same as before. The choice between vstack and concatenate often boils down to personal preference and the specific use case, as concatenate offers more flexibility with the axis of operation.

5. Stacking 1D Arrays:

vstack can also be used to stack 1D arrays, effectively turning them into rows in a 2D matrix.

Example:

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

stacked_array = np.vstack((array1, array2))

print(stacked_array)

Output:

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

6. Precautions:

Ensure that the arrays you're trying to stack have the same number of columns. If the shapes are incompatible, NumPy will raise a ValueError.

7. Conclusion:

Vertical stacking in NumPy is a handy operation, especially when assembling data from multiple sources or reformatting data structures. Both vstack and concatenate offer this capability, with vstack being a more specific and concise way to achieve vertical stacking.

1. Stacking arrays vertically in Python with NumPy:

Stacking arrays vertically involves combining multiple arrays along the vertical axis to create a new array.

import numpy as np

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

array2 = np.array([[7, 8, 9],
                   [10, 11, 12]])

# Perform vertical stacking using vstack
stacked_array = np.vstack((array1, array2))

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

2. How to use numpy.vstack for vertical stacking:

Use numpy.vstack to vertically stack arrays along the vertical axis.

# Assuming 'array1' and 'array2' are already defined

# Perform vertical stacking using vstack
stacked_array = np.vstack((array1, array2))

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

3. Numpy vertical stack example code:

Example code illustrating vertical stacking of two NumPy arrays.

# Assuming 'array1' and 'array2' are already defined

# Perform vertical stacking using vstack
stacked_array = np.vstack((array1, array2))

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

4. Python numpy stack arrays by rows:

Learn how to stack arrays by rows using the vertical stacking approach.

# Assuming 'array1' and 'array2' are already defined

# Perform vertical stacking using vstack
stacked_array = np.vstack((array1, array2))

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

5. Sample code for vertical stacking in numpy:

Sample code demonstrating vertical stacking of two arrays using NumPy.

# Assuming 'array1' and 'array2' are already defined

# Perform vertical stacking using vstack
stacked_array = np.vstack((array1, array2))

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

6. Numpy vertical stacking vs horizontal stacking:

Understand the difference between vertical stacking (vstack) and horizontal stacking (hstack) in NumPy.

# Assuming 'array1' and 'array2' are already defined

# Perform vertical stacking using vstack
stacked_array_vertical = np.vstack((array1, array2))

# Perform horizontal stacking using hstack
stacked_array_horizontal = np.hstack((array1, array2))

print("Array 1:")
print(array1)
print("\nArray 2:")
print(array2)
print("\nVertically Stacked Array:")
print(stacked_array_vertical)
print("\nHorizontally Stacked Array:")
print(stacked_array_horizontal)

7. Stacking a sequence of arrays vertically in numpy:

Explore stacking a sequence of arrays vertically using NumPy.

import numpy as np

# Create a sequence of NumPy arrays for vertical stacking
arrays = [np.array([1, 2, 3]),
          np.array([4, 5, 6]),
          np.array([7, 8, 9])]

# Perform vertical stacking using vstack
stacked_array = np.vstack(arrays)

print("Sequence of Arrays:")
for arr in arrays:
    print(arr)
print("\nVertically Stacked Array:")
print(stacked_array)

8. Python numpy vstack usage:

Understand the usage of numpy.vstack for vertically stacking arrays.

# Assuming 'array1' and 'array2' are already defined

# Perform vertical stacking using vstack
stacked_array = np.vstack((array1, array2))

print("Array 1:")
print(array1)
print("\nArray 2:")
print(array2)
print("\nVertically Stacked Array:")
print(stacked_array)
Copyright © devanddep.com | All Rights Reserved