A common need to is to from a Python list to a numpy array and back. Let's learn how to do both.

```
import numpy as np
# python list to numpy array
arr = np.array([1, 2, 3, 4])
print(arr)
# numpy array to python list
lst = list(arr)
print(lst)
```

And that's it! To go from a list to a numpy array, we use the `np.array`

function. To return from
a numpy array back to a python list, we use the `list()`

function.