# Add Column in NumPy

This tutorial will introduce the method to add a column to a NumPy array in Python.

## Add Column to a NumPy Array With the `numpy.append()`

Function

The `numpy.append()`

function can be used to add an extra column to an existing numpy array. The `numpy.append()`

function takes three parameters, the pre-existing array, the new values to be added, and the `axis`

by which we want to append the new values to the pre-existing array. We can specify the `axis`

parameter to `1`

if we want to add new columns to the pre-existing array. The `numpy.append()`

function returns a new array in which the new values are appended at the end of the pre-existing array. See the following code example.

```
import numpy as np
array = np.array([[1,2], [3,4], [5,6]])
array2 = np.append(array, [[1],[1],[1]], axis = 1)
array2
```

Output:

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

In the above code, we first initialized our first array `array`

with the `numpy.array()`

function in Python. We then initialized a new array, `array2`

, containing an extra column, with the `numpy.append()`

function in Python.