The `NameError: name 'np' is not defined`

is a common error that occurs when using the NumPy module in your code.

The stack trace is as follows:

```
Traceback (most recent call last):
File ...
data = np.array([1, 2, 3])
NameError: name 'np' is not defined
```

If you see a similar error, it means you didn’t alias the `numpy`

module as `np`

in the `import`

statement.

This article shows you the most common scenarios when this error may happen.

## 1. Using import numpy syntax

The most common import statement for `numpy`

is as follows:

```
import numpy as np
data = np.array([1, 2, 3])
```

The alias `as np`

isn’t required, but it’s nice to have as you don’t need to type `numpy`

when using NumPy’s functions and classes.

The `NameError`

is triggered when you import `numpy`

without an alias, but still type `np`

when you use its functions:

```
import numpy
data = np.array([1, 2, 3]) # ❌
data = numpy.array([1, 2, 3]) # ✅
```

The solution for this error depends on whether you want to use `np`

or `numpy`

in your code.

If you want to use `np`

, add `as np`

to the `import numpy`

statement.

Otherwise, replace all mentions of `np`

with `numpy`

in your code.

## 2. Using import * syntax

Sometimes, you may see starred import when importing the `numpy`

library as follows:

```
from numpy import *
```

The `import *`

syntax means you are importing the whole `numpy`

module into your code.

If you try to use the numpy module with `np`

name, you also get a `NameError`

:

```
from numpy import *
data = np.array([1, 2, 3]) # ❌
```

To fix this error, type the function directly as follows:

```
from numpy import *
data = array([1, 2, 3]) # ✅
```

Please note that it’s discouraged to use starred imports in Python because it can cause confusion.

Using regular or named imports makes it easy to identify which module is used because the module name is invoked.

Since you want to use the `np`

name, then the best fix is to use a named import as follows:

```
import numpy as np
data = np.array([1, 2, 3]) # ✅
```

Most developers do like to alias `numpy as np`

because it’s shorter and easier to type.

Now you’ve learned how to fix `NameError: name 'np' is not defined`

.

I hope this article was helpful. See you in other tutorials! 👋