Arrays in Python: What are Arrays in Python & How to Use Them?

Python has emerged as a top programming language in terms of capabilities and usage around the world. Today, we are here to make you familiar with one of the simplest data structures for coding, i.e. arrays. 

So if you wish to learn about array in Python, keep reading this tutorial till the end to understand how to find the length of an array in Python. 

Explaining Python array

An array in Python refers to a collection that has multiple items saved together in contiguous memory chunks. Simply put, these locations hold many items of identical data type in a sequential arrangement. Let us understand this with an example: Imagine a fleet of stairs where each step denotes a value. And suppose that your friends are standing on different steps of this stairway. You can find the location of any one of your friends by simply knowing the count of the stair they are standing on. 

Python has a specific module called “array,” which you can use to manipulate specific values. You can create lists where all elements must have the same data type. With a data structure like an array, you are able to access numerical data from a defined series, fetching the required values by specifying an index number. (Note: The index begins from 0, and the stored items are called elements).  

Furthermore, you can change the array and perform several data manipulations, depending on your needs. But before we explore that in detail, we should address a common point of consumption.

Although both Python arrays and lists store values in a similar manner, there exists a fundamental distinction between the two. While a list stores anything from integers to strings, an array can only have single value types. Therefore, you come across an array of strings, an array of integers, and so on. 

Checkout: Python Open Source Project & Topics

When and Why do We use Arrays?

We typically utilize the Python array module for purposes like interfacing with code written C. Arrays offer an easier way of storing C-style data types faster and with less memory space. 

Moreover, a combination of arrays with Python is also time-efficient. It reduces the overall size of your code and enables you to avoid problematic syntax, a major concern with other languages. 

For instance, if you had to store 100 variables with different names, it makes sense to store them as integers (1-100). It is a far better option to save them using an array instead of spending time remembering their names. 

Using array in Python

Let us take it one step at a time:

  1. Import the array module
  2. Create an array list (Specify the data type and value list as arguments)
  3. Add elements to the array using insert() and append()
  4. Start accessing elements 
  5. Update elements, as desired (Slice, change, remove)
  6. Search elements
  7. Find the array’s length

Now that you are aware of the different operations of using an array in Python, let us look at the sample code. 

  • To import the module, you simply use the ‘import’ command followed by the qualifier — let this be ‘jam’. 

import array as jam 

a = jam.array(‘o’,[1.2,3.6,4.7])

print (a)

This would display the following output:


  • If you want to access a specific element of an array, you can use a code like this:

import array as cam

b = cam.array(‘i’,[1,3,5,7])

print(“1st element:”,b[0])

print(“2nd element:”, b[1])

print(“Last element:”, b[-1])

The output would be shown as follows:

First element: 1

Second element: 3

Last element: 7

  • The following sample code will help you understand how to slice a part of the Python array

import array as mac

numbers_list = [22, 5, 42, 5, 52, 48, 62, 5]

numbers_array = mac.array(‘j’,numbers_list)

print(numbers_array[3:6]) # 4th to 6th

print (numbers_array[:-5]) # beginning to 4th

print (numbers_array[4:]) #5th to end

print (numbers_array[:]) #beginning to end 

This code will give you an output with specific integer values that you mentioned; see below:

array(‘j’,[5, 52, 48])

array(‘j’,[22, 5, 42])

array(‘j’,[52, 48, 62, 5])

array(‘j’,[22, 5, 42, 5, 52, 48, 62, 5)

  • Since a Python array is mutable, you can alter the items, add more elements, and remove others. Check out these examples: 

import array as pac

numbers = pac.array( ‘m’, [5, 10, 7, 1, 2, 3])                           

#to change the first element 

numbers[0] = 6


# Output: 

array(‘m’ , [6, 10, 7, 1, 2, 3])

#to change the fourth element to fifth element

numbers[3:4] = pac.array( ‘m’, [8, 9, 4])

Then, write the command to print the output array.

# Output: 

array(‘m’, [6, 10, 7, 8, 9, 4]) 

If you want to add a new item to the array, you can use the append() method. Alternatively, you can add many new items using the extend() method. We have demonstrated this for more clarity:

import array as dac

numbers = dac.array(‘i’, [3, 4, 5])


Upon printing the output, you will get: 

#Output: array(‘i’, [3, 4, 5, 6])

# extend() to append iterable items to the end


Again, print the output to get the array:

array(‘i’, [3, 4, 5, 6, 7, 8, 9])

Similarly, you can remove one or more items using the del statement in Python. Let’s use the same array for this demonstration. 

del number[1] # to remove second element

print number() 


array ( ‘i’, [3, 5, 6, 7, 8, 9])

You can also use the remove() function to delete a specific item and implement pop() to remove any given index. 



array ( ‘i’, [3, 5, 6, 7, 9])

  • If you intend to search for a particular element, you can use index(), an in-built method in Python that returns the index of the first occurrence of the argument value.

With this, we have given you a refresher on what are arrays in Python and their usage. You may also be interested in finding the array length. Here, length refers to how many elements are present in the Python array. You can use the len() function to determine the length. It is as simple as inputting the len(array_name) statement, and a value (integer) will be returned. 

Take, for example, this array:

a=arr.array(‘f’, [2.1, 4.1, 6.1, 8.1])


#Output: 4

As you can see, the value returned is equal to the number of elements in the Python array.

Read: Python Interview Questions & Answers


Now you know what are arrays in Python, their usage, along with how to find the length of the array in Python. This information will help you strengthen your Python programming skills. So, keep practising!

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