# How does numpy.newaxis work and when to use it?

Hello Guys, How are you all? Hope You all Are Fine. Today We Are Going To learn about How does numpy.newaxis work and when to use it in Python. So Here I am Explain to you all the possible Methods here.

## How does numpy.newaxis work and when to use it?

1. How does numpy.newaxis work and when to use it?

You started with a one-dimensional list of numbers. Once you used `numpy.newaxis`, you turned it into a two-dimensional matrix, consisting of four rows of one column each.

2. numpy.newaxis work and when to use it

You started with a one-dimensional list of numbers. Once you used `numpy.newaxis`, you turned it into a two-dimensional matrix, consisting of four rows of one column each.

## Method 1

You started with a one-dimensional list of numbers. Once you used `numpy.newaxis`, you turned it into a two-dimensional matrix, consisting of four rows of one column each.

You could then use that matrix for matrix multiplication, or involve it in the construction of a larger 4 x n matrix.

## Method 2

`newaxis` object in the selection tuple serves to expand the dimensions of the resulting selection by one unit-length dimension.

It is not just conversion of row matrix to column matrix.

Consider the example below:

```In [1]:x1 = np.arange(1,10).reshape(3,3)
print(x1)
Out[1]: array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]])
```

Now lets add new dimension to our data,

```In [2]:x1_new = x1[:,np.newaxis]
print(x1_new)
Out[2]:array([[[1, 2, 3]],

[[4, 5, 6]],

[[7, 8, 9]]])
```

You can see that `newaxis` added the extra dimension here, x1 had dimension (3,3) and X1_new has dimension (3,1,3).

How our new dimension enables us to different operations:

```In [3]:x2 = np.arange(11,20).reshape(3,3)
print(x2)
Out[3]:array([[11, 12, 13],
[14, 15, 16],
[17, 18, 19]])
```

Adding x1_new and x2, we get:

```In [4]:x1_new+x2
Out[4]:array([[[12, 14, 16],
[15, 17, 19],
[18, 20, 22]],

[[15, 17, 19],
[18, 20, 22],
[21, 23, 25]],

[[18, 20, 22],
[21, 23, 25],
[24, 26, 28]]])
```

Thus, `newaxis` is not just conversion of row to column matrix. It increases the dimension of matrix, thus enabling us to do more operations on it.

## Conclusion

It’s all About this issue. Hope all Methods helped you a lot. Comment below Your thoughts and your queries. Also, Comment below which Method worked for you? Thank You.