# How to concatenate two arrays in NumPy

You can concatenate two arrays in NumPy with the following code. If you want to learn Python, I highly recommend reading This Book.

## Example 1

In this example, I will concatenate two arrays row-wise.

```# Import NumPy library
import numpy as np

# Make NumPy arrays
a = np.array([[5, 10],
[15, 20]])
b = np.array([[100, 200]])

# Concatenate arrays row wise
print(np.concatenate((a, b), axis=0))```

Output:

```[[  5  10]
[ 15  20]
[100 200]]```

## Example 2

In this example, I will concatenate two arrays column-wise.

```# Import NumPy library
import numpy as np

# Make NumPy arrays
a = np.array([[5, 10],
[15, 20]])
b = np.array([[100, 200]])

# Concatenate arrays Column wise
print(np.concatenate((a, b.T), axis=1))```

Output:

```[[  5  10 100]
[ 15  20 200]]```

## Example 3

```# Import NumPy library
import numpy as np

# Make NumPy arrays
a = np.array([[5, 10],
[15, 20]])
b = np.array([[100, 200]])

# Concatenate arrays
print(np.concatenate((a, b), axis=None))```

Output:

`[  5  10  15  20 100 200]`