Convert array to list Python
In this post, you will learn how to convert an array to a list using the Python programming language.
Arrays and lists are the most commonly used data structures in the Python programming language. An array is a container that can hold a fixed number of items, and these items should be of the same type. A list is a sequence of indexed and ordered values. It contains a list of any type of data object with a comma separated and enclosed within a square bracket. In the development process, we may come across a situation where we need to convert an array to a list. Python provides an in-built method tolist(), to convert an array to a list.
If the array is one-dimensional, a list with the array elements is returned, and if the array is multi-dimensional, a nested list is returned.
Converting array to list using numpy tolist() method
We can convert an array to a list of data elements with the help of the ndarray.tolist() method. The numpy ndarray object has a handy tolist() method that can be used to convert the respect numpy array to a list. This method doesn't accept any arguments and returns a copy of the array data as a Python list.
In the given Python program, we have converted the one-dimensional numpy array to a list.
import numpy as np
arr = np.array([2,4,6])
numpy_arr = np.array(arr)
# printing my_array
print("Array - \n")
print(numpy_arr)
# convert array to list
numpy_list = numpy_arr.tolist()
print("List - ",numpy_list)
Output of the above code -
Array -
[2 4 6]
List -
[2, 4, 6]
Converting multi-dimensional array to list
In the given example, we have converted a multidimensional array to a list of data elements with the help of the tolist() method.
import numpy as np
arr = np.array([[2,4,6],[3,1,4],[5,3,6]])
numpy_arr = np.array(arr)
# printing my_array
print("Array - \n")
print(numpy_arr)
# convert array to list
numpy_list = numpy_arr.tolist()
print("List - ",numpy_list)
Output of the above code -
Array -
[[2 4 6]
[3 1 4]
[5 3 6]]
List -
[[2, 4, 6], [3, 1, 4], [5, 3, 6]]
Converting array to list using array class
Here, first we are importing an array class to use an array. Then, we convert an array to a list of data elements with the help of the tolist() method.
import array as arr
# declare array
x = arr.array ("i", [5, -4, -50, 35, 11])
# declare an empty list
y = list()
# convert array and assign to the list
y = x.tolist()
# print list
print ("Created list : ", y)
Output of the above code -
Created list : [5, -4, -50, 35, 11]
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