.tolist()

Anonymous contributor
Anonymous contributor
Published Jun 29, 2024
Contribute to Docs

The `.tolist()` function in NumPy converts an array into a nested Python list and returns it. Each element in the array is converted into the closest compatible built-in Python type using the `.item()` function. The attribute `a.ndim` represents the number of dimensions (axes) of the array. When `a.ndim` is 0, the result of the operation is a simple scalar, as the depth of the nested list is 0.

Syntax

``````ndarray.tolist()
``````
• `ndarray`: The array to be converted.

Example

The following example creates an `ndarray` named `arr` and converts it into a nested Python list `arr_list` using `.tolist()`:

```import numpy as np
# Creating an arrayarr = np.uint32([1, 2])
# Converting the array into a Python list using list()arr_list = list(arr)
# Checking the outputprint(arr_list)
# Checking the output typeprint(type(arr_list[0]))
# Converting the array into a Python list using .tolist()arr_tolist = arr.tolist()
# Checking the outputprint(arr_tolist)
# Checking the output typeprint(type(arr_tolist[0]))
```

This produces the following output:

```[1, 2]<class 'numpy.uint32'>[1, 2]<class 'int'>
```

As observed, although the resulting lists are similar, i.e., `[1, 2]`, the types of their elements differ when using `list()` versus `.tolist()`.

Codebyte Example

Here is a codebyte example to understand the working of the `.tolist()` function for converting a 2D array into a Python list:

`usVisit uscodeHide codeCodeOutputHide outputHide outputLoading...`