Python Array extend() Method

The Python array extend() method is used to add more than one element from the given iterable[list/tuple] to the current array.

Similar to the append() method, when we add elements using this they are inserted at the end of the array.

The major difference between these two methods is that using the append() method we can insert/add more than one element.

Syntax

Following is the syntax of Python array extend() method −

array.extend(iterable)

Parameters

This method accepts iterable(list / tuple) that can be extended.

Return Value

This method does not return any value.

Example 1

Following is the basic example of the Python array extend() method.

Here, we have created an array with name my_array (of int data-type), and added the contents of a list (iterable) to it −

import array as arr
#Creating an array
my_array1 = arr.array('i',[1,2,3,4])
#Printing the elements of an array
print("Array Elements : ", my_array1)
#adding elements using extend method
list1=[100,13,15]
my_array1.extend(list1)
print("Elements After Extending : ", my_array1)

Output

Following is the output of the above code −

Array Elements :  array('i', [1, 2, 3, 4])
Elements After Extending :  array('i', [1, 2, 3, 4, 100, 13, 15])

Example 2

When we extend iterables of different data-type to that of an array we will get TypeError.

In the following example, we have created an array of int datatype and extended it by adding floating point values it −

import array as arr
#Creating an array
my_array2 = arr.array('i',[1,2,3,4])
#Printing the elements of an array
print("Array Elements : ", my_array2)
list2=[4.66,75.8,34.7]
my_array2.extend(list2)
print("Elements After Extending", my_array2)

Output

E:\pgms>python extendprg.py
Array Elements :  array('i', [1, 2, 3, 4])
Traceback (most recent call last):
  File "E:\pgms\extendprg.py", line 32, in <module>
    my_array2.extend(list2)
TypeError: 'float' object cannot be interpreted as an integer

Example 3

Let try another example. Here we created an array of float datatype and extended it using floating point values −

import array as arr
#Creating an array
my_array3 = arr.array('d',[3.5,2.66,3.9,4.90])
#Printing the elements of an array
print("Array Elements: ", my_array3)
list3=[50.66,60.8,100.7]
my_array3.extend(list3)
print("Elements After Extending: ", my_array3)

Output

Array Elements:  array('d', [3.5, 2.66, 3.9, 4.9])
Elements After Extending array('d', [3.5, 2.66, 3.9, 4.9, 50.66, 60.8, 100.7])

Example 4

In the above example we used only list iterable. Now, lets try with another iterable i.e tuple −

import array as arr
#Creating an array
my_array4 = arr.array('i',[3,2,39,490])
#Printing the elements of an array
print("Array Elements : ", my_array4)
tup1=(30,100,40,11)
my_array4.extend(tup1)
print("Elements After Extending : ", my_array4)

Output

Array Elements :  array('i', [3, 2, 39, 490])
Elements After Extending :  array('i', [3, 2, 39, 490, 30, 100, 40, 11])