9951 explained code solutions for 126 technologies

python-scipyHow do I use the numpy vstack function in Python?

np.vstack is a function in the NumPy library used to stack arrays in sequence vertically (row wise). It takes a sequence of arrays of the same shape as arguments and returns a single array that is a concatenation of all of the input arrays.

Example

import numpy as np

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

c = np.vstack((a,b))

print(c)

Output example

[[1 2 3]
[2 3 4]]

The code above uses the np.vstack function to stack two arrays a and b vertically. The output is a single array c that is the concatenation of a and b.

The parts of the code are as follows:

• import numpy as np: This imports the NumPy library as np, which provides access to the vstack function.

• a = np.array([1, 2, 3]): This creates an array a with elements 1, 2, 3.

• b = np.array([2, 3, 4]): This creates an array b with elements 2, 3, 4.

• c = np.vstack((a,b)): This uses the np.vstack function to stack a and b vertically.

• print(c): This prints the output of the np.vstack function.