# How to Concatenate Two Columns Matrix in Python?

To concatenate two columns of a matrix in Python, you can use the NumPy library. NumPy provides the `concatenate()` function to combine arrays along a specified axis. Here’s an example:

``````import numpy as np

# Create a sample matrix
matrix = np.array([[1, 2],
[3, 4],
[5, 6]])

# Extract two columns
column1 = matrix[:, 0]
column2 = matrix[:, 1]

# Concatenate the two columns horizontally
concatenated_matrix = np.concatenate((column1[:, np.newaxis], column2[:, np.newaxis]), axis=1)

print(concatenated_matrix)``````

In this example, we have a sample matrix with three rows and two columns. We want to concatenate the two columns horizontally.

To accomplish this, we extract the two columns from the matrix using slicing. `matrix[:, 0]` extracts the first column, and `matrix[:, 1]` extracts the second column.

Then, we use the `concatenate()` function from NumPy to concatenate the two columns horizontally. The function takes a tuple of arrays to concatenate, and the `axis=1` argument specifies the horizontal concatenation.

Note that we use `[:, np.newaxis]` to reshape each column to have a single column shape before concatenating them. This ensures that the arrays have compatible shapes for concatenation.

Finally, we print the concatenated matrix, which contains the two columns combined horizontally.

Make sure to import the NumPy library (`import numpy as np`) before using the code.