# Numpy – Set All Values to Zero in Array

The Numpy library in Python comes with a number of built-in functions to manipulate the data in arrays. In this tutorial, we will look at a function that helps us set all the values in a Numpy array to zero.

## How to set all values to zero in Numpy?

You can use the `numpy.ndarray.fill()` function to set all the values in a Numpy array to zero. Pass `0` as the argument (this is the value used to fill all the values in the array).

The following is the syntax –

```# set all values in numpy array ar to 0
ar.fill(0)```

It modifies the array in-place, filling each value with zero (the passed value).

Let’s now look at a step-by-step example of using the above function.

### Step 1 – Create a Numpy array

First, we will create a Numpy array that we will use throughout this tutorial.

```import numpy as np

# create a numpy array
ar = np.array([-2, -1, 0, 1, 2, 3, -4])
# display the array
print(ar)```

Output:

`[-2 -1  0  1  2  3 -4]`

Here, we used the `numpy.array()` function to create a Numpy array containing some numbers.

### Step 2 – Set each value to `0` using `numpy.ndarray.fill()`

Apply the `numpy.ndarray.fill()` function on the array and pass `0` as the parameter to set each value to zero in the array.

Let’s apply this function to the array created above.

```# set all values to zero
ar.fill(0)
# display the array
print(ar)```

Output:

`[0 0 0 0 0 0 0]`

You can see that each value in the array `ar` is now `0`.

The `numpy.ndarray.fill()` function works similarly on higher-dimensional arrays. For example, let’s apply this function to a 2D array of some numbers.

```# create 2D numpy array
ar = np.array([[-1, 2, -3],
[0, 51, 7],
[1, 125, 8]])
# set all values to zero
ar.fill(0)
# display the array
print(ar)```

Output:

```[[0 0 0]
[0 0 0]
[0 0 0]]```

You can see that each value in the above 2D array is now zero.

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