The **numpy.asmatrix()** function **“interprets the input as a matrix”**. If the input is already a matrix or a ndarray of 2 dimensions, it returns the input as is. If the input is a different data type, such as a list or a tuple, it converts it into a matrix.

**Syntax**

`numpy.asmatrix(data, dtype=None)`

**Parameters**

**data: (array_like)**

We provide the input as an array to convert that into the matrix.

**dtype:(data-type)**

The data type of the resultant matrix, formed via the asmatrix function, is provided by default; it’s the same as the inputted data.

**Return Value**

It takes the inputted array and converts that into a matrix. It doesn’t make a copy of a matrix, or ndarray is passed to it. The data type of the output matrix is the same as the inputted array.

**Example**

```
import numpy as np
x = np.array([[1, 2], [3, 4]])
m = np.asmatrix(x)
print(m)
print('Manipulating the matrix formed via asmatrix function')
x[0, 0] = 5
print(m)
a = np.asmatrix(np.zeros((3, 1)))
print(a)
```

**Output**

```
[[1 2]
[3 4]]
Manipulating the matrix formed via asmatrix function
[[5 2]
[3 4]]
[[0.]
[0.]
[0.]]
```

That’s it.