Numpy arrays are **a grid of values** of the same type. You can use these arrays to store a list of values that needs to be used for data analysis or machine learning activities.

**You can normalize a NumPy array to a unit vector using the sklearn.normalize() method.**

When using the array of data in machine learning, you can only pass the normalized values to the algorithms to achieve better accuracy. A unit vector is a vector that has a magnitude of `1`

.

In this tutorial, you’ll learn how to normalize a `NumPy`

array to a unit vector using the python libraries `sklearn.normalize()`

and `numpy.norm()`

method.

**If You’re in Hurry…**

You can use the below code snippet to normalize an array in `NumPy`

to a unit vector.

`np.linalg.norm()`

method will return one of eight different matrix norms or one of an infinite number of vector norms depending on the value of the `ord`

parameter. If you do not pass the `ord`

parameter, it’ll use the FrobeniusNorm.

When you divide the data using this Norm, you’ll get normalized data as shown below.

**Snippet**

```
import numpy as np
x = np.random.rand(10)*10
normalized_x=
````x/np.linalg.norm(x)`
print(normalized_x)

**Output**

```
[0.46925769 0.12092959 0.37642505 0.09316824 0.38277321 0.07894217
0.36265182 0.28934431 0.49484541 0.04406218]
```

This is how you can get a unit vector of a NumPy array.

**If You Want to Understand Details, Read on…**

In this tutorial, you’ll learn how to get the unit vector from a NumPy array using different methods.

Table of Contents

## Sample Numpy Array

First, let’s create a sample `NumPy`

array with `10`

random values. You can use this in the later steps to learn how to normalize the data.

**Snippet**

```
import numpy as np
from sklearn.preprocessing import normalize
x = np.random.rand(10)*10
x
```

**Output**

```
array([4.59743528, 2.49994446, 5.45313476, 2.22769086, 3.19143523,
8.56257209, 7.01471989, 6.23370745, 7.21487837, 8.86694182])
```

## Using SKlearn Normalize

In this section, you’ll learn how to normalize a `NumPy`

array using the sklearn `normalize()`

method.

Normalize() method scales the input vector to an individual unit norm.

It accepts one **mandatory** parameter.

`X`

– Array-like input. You can pass the data to be normalized in this parameter.

**Parameters**

It also accepts three other **optional **parameters.

`norm`

– *{‘l1’, ‘l2’, ‘max’}, default=’l2’* – The norm to be used for normalizing the data.

`axis`

– *{0, 1}, default=1* – axis used to normalize the data along. If `1`

, each sample will be normalized individually, If `0`

, each feature will be normalized.

`copy`

– *bool, default=True* – If `false`

, the normalization will take place in the same instance of the array. Otherwise, a new copy of the array will be created and normalized.

`return_norm`

– *bool, default=False* – Whether you need the computed norms to be returned or not.

**Snippet**

`normalize(x[:,np.newaxis], axis=0)`

is used to normalize the data in variable `X`

.

Where,

`np.newaxis`

increases the dimension of the NumPy array. Using it along the array X will make the array a one-dimensional array.

`x[:, np.newaxis]`

– To return all rows from the array for normalization.`axis=0`

– To normalize the each feature in the array

```
import numpy as np
from sklearn.preprocessing import normalize
x = np.random.rand(10)*10
normalized_x =
````normalize(x[:,np.newaxis], axis=0)`
print(normalized_x)

When you print the array, you’ll see the array is in a normalized form.

**Output**

```
[[0.05341832]
[0.42901918]
[0.34359858]
[0.00150131]
[0.48057246]
[0.3178608 ]
[0.27146542]
[0.27559803]
[0.37805814]
[0.26545377]]
```

## Using np.linalg.norm()

You can also use the `np.linalg.norm()`

method from the NumPy library to normalize the NumPy array into a unit vector.

`np.linalg.norm()`

method will return one of eight different matrix norms or one of an infinite number of vector norms depending on the value of the `ord`

parameter. If you do not pass the `ord`

parameter, it’ll use the FrobeniusNorm.

You can divide the data using the returned norm to get the unit vector of the NumPy array.

**Snippet**

```
import numpy as np
x = np.random.rand(10)*10
normalized_x=
````x/np.linalg.norm(x)`
print(normalized_x)

When you print the normalized vector, you’ll see the normalized value as shown below.

**Output**

```
[0.46925769 0.12092959 0.37642505 0.09316824 0.38277321 0.07894217
0.36265182 0.28934431 0.49484541 0.04406218]
```

This is how you can use the `np.linalg.norm()`

method to normalize the `NumPy`

array to a unit vector.

## Using Maths Formula

In this section, you’ll create a maths formula to normalize the `NumPy`

array to a unit vector.

You’ll create a vector norm by taking the square root of the sum of the values in the array. Then using this vector, you can create a normalized form of the data.

Use the below form to normalize the `NumPy`

array using the mathematical form.

**Snippet**

```
import numpy as np
x = np.random.rand(10)*10
normalized_x =
````x / np.sqrt(np.sum(x**2))`
print(normalized_x)

**Output**

```
[0.12280124 0.36840538 0.05669781 0.27392538 0.43742201 0.45143303
0.20542178 0.03980713 0.13138495 0.5610464 ]
```

This is how you can normalize a NumPy array into a unit vector by using the mathematical formula.

## Normalize Numpy Array Along Axis

In this section, you’ll learn how to normalize the NumPy array into a unit vector along the different axis. Namely, `row`

axis and `column`

axis.

### Normalize Numpy Array By Columns

You can use the `axis=0`

in the normalize function to normalize the NumPy array into a unit vector by columns. When you use this, **each feature of the dataset will be normalized.**

**Snippet**

```
import numpy as np
from sklearn.preprocessing import normalize
x = np.random.rand(10)*10
normalized_x =
````normalize(x[:,np.newaxis], axis=0)`
print(normalized_x)

This array has only one feature. Hence, when you print the normalized array, you’ll see the below values.

**Output**

```
[[0.23542553]
[0.38018535]
[0.05725614]
[0.01711471]
[0.59367405]
[0.58159005]
[0.04489816]
[0.09942305]
[0.1961091 ]
[0.23538758]]
```

### Normalize Numpy Array By Rows

You can use the `axis=1`

in the normalize function to normalize the NumPy array into a unit vector by rows. When you use this, **each sample of the dataset will be normalized individually.**

**Snippet**

```
import numpy as np
from sklearn.preprocessing import normalize
x = np.random.rand(10)*10
normalized_x =
````normalize(x[:,np.newaxis], axis=1)`
print(normalized_x)

The array has only one column. When you normalize based on the row, each sample will be normalized and you’ll see the output as below.

**Output**

```
[[1.]
[1.]
[1.]
[1.]
[1.]
[1.]
[1.]
[1.]
[1.]
[1.]]
```

This is how you can normalize the NumPy array by rows. Each sample will be sample individually.

## Conclusion

To summarize, you’ve learned how to normalize a `NumPy`

array into a unit vector for using it for various data analysis purposes.

You’ve also learned how to get the unit vector from a NumPy array using the maths formula, NumPy `norm()`

method, and the sklearn `normalize()`

method.

If you’ve any questions, comment below.