# Python NumPy to list with examples

In this Python NumPy tutorial, we will discuss Python NumPy to list and also cover the below examples:

• Python numpy list to array
• Python numpy list to matrix
• Python numpy list to ndarray
• Python numpy list to string
• Python numpy list to CSV
• Python numpy array to list of strings
• Python numpy array to list of tuples
• Python numpy tuple to list
• Python numpy array to list of lists

## Python numpy to list

• In this section, we will learn about python numpy to list.
• Python stores data in several different ways but the most popular methods are lists and dictionaries.
• Arrays are also a data structure that is used to store the data.
• These arrays are similar to the list.
• Both lists and arrays are used for storing data.
• The LIst is mutable as well as array is mutable. So we can add and remove an element from the list and array.
• Both can be indexed and iterated.
• Both can be slicing operations.
• List are containers for elements having different datatype but arrays as containers for elements of the same datatype.
• We can store int, float, string in a single list but in arrays, we need to store the same type of data.

Syntax:

Here is the Syntax of the numpy array to list

``numpy.ndarray.tolist()``
• It returns a copy of the array data as a python list and the possible nested list of array elements.

Example:

``````import numpy as np

arr1= np.array([2, 4, 5])
list1 = arr1.tolist()
print(list1)``````

Here is the Screenshot of following given code

The above code we can use to convert NumPy to list in Python.

## Python numpy list to array

• In this section, we will learn about python numpy list to an array.
• In python, the list can be converted to arrays by using two methods from the numpy library.
• In this method, we can easily use the function using numpy. array().
• First, we import a numpy library and then initialize a list, and converting the list to an array.

Example:

``````import numpy

list = [2, 4, 8, 9, 2, 5, 6]
arr1 = numpy.array(list)
print(arr1)``````

Here is the Screenshot of the following given code

## Python numpy list to matrix

• In this section, we will learn about python’s numpy list to a matrix.
• Use the np. array(list) function to convert a list into a matrix form.
• The np. array function takes an iterable and returns a numpy array.

Example:

``````import numpy

list = [2, 4, 8],[9, 2, 5]
arr1 = numpy.array(list)
print(arr1)``````

Here is the Screenshot of following given code

This is how to convert numpy list to matrix in Python.

## Python numpy list to ndarray

• In this section, we will learn about python numpy list to ndarray.
• ndarray is a (usually fixed-size) multidimensional container of items of the same type and size.
• First, we have to import a package and declare the nested 4-d list, and then use numpy.array() function to convert the list to the array and contain it in a different object.
• It returns in the matrix form and displays the result in a numpy array.

Example:

``````import numpy

list = [2, 4, 8,4],[9, 2, 5,4],[1,3,4,5],[3,4,5,6]
arr1 = numpy.array(list)
print(arr1)``````

Here is the Screenshot of following given code

This is an example of how to covert numpy list to ndarray in Python.

## Python numpy list to string

• In this section, we will learn about python numpy list to string.
• In this method, we are using the join() function.
• First, we have to create a function list to string and initialize an empty string.
• And it will return the string.
• The list will contain both string and integer as its element.

Example:

``````import numpy as np
def lToS(list1):

str2 = " "

return (str2.join(list1))
list1 = ['John', 'GEORGE', 'MICHEAL']
print(lToS(list1))``````

Here is the Screenshot of following given code

• Another method from numpy list to string by using map() method.
• Use map() method for converting elements in the list to string.

Example:

``````import numpy as np

str1 = ['Mango','Onion','Apple']
listToStr = ' '.join(map(str, str1))
print(listToStr) ``````

Here is the Screenshot of following given code

This is how to convert a numpy list to a string in Python.

## Python numpy list to CSV

• In this section, we will learn about the numpy list to CSV.
• The CSV file is opened as a file with Python’s built-in open() method, which returns a file object.
• In this method, we use the dataframe function to store the list in a dataframe and we simply export it to a CSV file using to_csv.

Example:

``````import numpy as np
import pandas as pd

list = [2,3,4,5,6,7,8]
print(list)
DF = pd.DataFrame(list)
DF.to_csv('/home/arvind/Documents/test.csv')``````

Here is the Screenshot of following given code

## Python numpy array to list of strings

• In this section, we will learn about the numpy array to list strings.
• In this method, we can easily use the method list().it converts the array into a list.
• In the list, we can easily use the str characters.
• It always returns a copy of the numpy array data as a list.

Example:

``````import numpy as np

a = np.array([['john','George', 'Micheal'], ['orange', 'apple', 'grapes']])
list1 = a.tolist()
print(list1)``````

Here is the Screenshot of the following given code

This is how to convert numpy array to list of strings in Python.

## Python numpy array to list of tuples

• In this section, we will learn about the numpy array to list tuples.
• In this method, we can easily use map and tuple functions.
• This function returns a map object of the results after applying the given function to each item of a given sequence iterable.
• A tuple is a method in Python that has items separated by commas and enclosed in open brackets.

Example:

``````import numpy as np

arr = np.array([['mango', 'apple'], ['grapes', 'orange']])
res = tuple(map(tuple, arr))
print(res) ``````

Here is the Screenshot of following given code

## Python numpy tuple to list

• In this section, we will learn about the numpy tuple to list
• Tuple cannot be changed because it’s immutable but in the list, we can add new values and elements.
• Tuple uses open brackets whereas list uses square brackets.
• In Python, the list() method takes iterable sequence types and converts them to lists. This is used to convert a given tuple into a list.
• The output will always in the form of a list.

Example:

``````import numpy as np
Tup = (456, 'tuv', 'mno', 'klm')
List1 = list(Tup)
print(List1)``````

In the above example first, we create a tuple and then use the function list() and convert them into the list.

Here is the Screenshot of following given code

This is how to convert numpy array to list of tuples in Python.

## Python numpy array to list of lists

• In this section, we will learn about the numpy array to list of lists.
• In Python’s numpy module, the numpy dimension array class provides a function tolist(), which returns a list containing the copy of all the values in the numpy array. If the numpy array is 2Dimension, then it returns a list of lists.
• List are containers for values having different dtype but numpy arrays as containers for elements of the same datatype.
• The output will be in the form of lists into the list.

Example:

``````import numpy as np

arr1 = np.array([[4, 5, 6, 7],
[5, 4, 4, 9],
[3, 4, 5, 6]])

listoflists = arr1.tolist()
print(listoflists) ``````

Here is the Screenshot of the following given code

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In this Python NumPy tutorial, we will discuss Python NumPy to list and also cover the below examples:

• Python numpy list to array
• Python numpy list to matrix
• Python numpy list to ndarray
• Python numpy list to string
• Python numpy list to CSV
• Python numpy array to list of strings
• Python numpy array to list of tuples
• Python numpy tuple to list
• Python numpy array to list of lists