Python is a popular object-oriented programming language that we use for a variety of purposes, including software development, data analysis, and backend web development. The language, created by Guido van Rossum in 1991, is easy to use thanks to its readability. The language features thousands of third-party packages giving developers access to numerous additional functions.
Python is a great programming language for everyone to learn, but it features several benefits that make it an excellent choice for beginners. Python uses simple syntax, making it more readable than other languages, which means it’s easy to start with. Additionally, Python works in a variety of contexts, which means you can build powerful applications shortly after learning the basics.
Developers, corporations, and hobbyists around the world use Python. Large companies such as Slack, DigitalOcean, and Fastly, Netflix, Google, and Mozilla all prefer the language, as you can use Python for almost anything!
In this guide, we are going to break down a few of the most useful topics that beginner Python developers should know. We’ll cover topics such as how to get user input, how to manipulate strings, how to write comments, how to sort data and more. Additionally, we’ll also explore a few advanced programming concepts that may be useful for you to know, such as how to create queues and how to zip data together.
If you’re a Python beginner who is looking for a guide into the language, this article is for you! We have also linked to our interactive Python tutorials on each concept, which include source code for the concepts we discuss. Now, let’s delve into some of the most useful Python functions you should learn.
When you’re working with a string, you may want to split it up into different parts. For example, you may want to split up a user’s name into two variables: first name and surname. Or you may want to get the last four numbers in a user’s ID.
By using the Python slicing approach, you can retrieve this data. Slicing allows you to get a specific part of a string and create a
substring. Here’s the syntax to get a substring from a larger string:
ourString = "This is an example sentence." ourString[startNumber:endNumber]
enumerate() Python function allows you to loop through a list of items while keeping track of the index value in a separate variable. This function is useful if you have an array that you want to loop through, and where you want to keep track of the index value of each item. Here is an example of the
enumerate() function’s Python syntax:
array_name = ['Item One', 'Item Two', 'Item Three'] for index, value in enumerate(array_name): print(index, value)
Retrieving and processing input from a user is a crucial part of programming. Let’s say you are writing a program that collects a student’s numerical grade on a test and tells them whether they earned an A, B, C, D, or failed the test. You would need to get the user’s grade.
input() function allows you to retrieve information through the keyboard, which you can then process in your program. Here is the syntax for retrieving user input in Python 2.x:
email = raw_input("Enter your email address: ") print "To confirm, is your email address:", email
Here’s the syntax of
input() in Python 3:
email = input("Enter your email address: ") print("To confirm, is your email address:", email)
When you’re working in Python, you may want to create a set of dictionaries from two arrays. For example, you may have three arrays that store a user’s name, their customer ID, and their email address, that you want to merge into one. That’s where the
zip() function comes in.
zip() allows you to create a list of tuples which contain elements from the iterable items — such as a list, set, tuple, or dictionary — that you have passed into the
zip() function. Here’s an example of the
zip() function in action:
employee_numbers = [2, 9, 18, 28] employee_names = ["Candice", "Ava", "Andrew", "Lucas"] zipped_values = list(zip(employee_names, employee_numbers))
Comments allow you to take notes on your code that will be ignored by the compiler. There are a couple of reasons why developers write comments. If you’re working on a big program, comments can help you keep track of each operation; comments can help teams ensure that everyone can read each other’s code; if you’re fixing a bug, comments can help you keep track of your thoughts.
In Python, you can write comments using the number sign
# This is a comment
You can also use the
# character to comment out your code if you want it to be skipped by the compiler:
if numericalGrades[s] >= 60: print("test") # print(students[ss], "passed their test.") else: print(students[s], "failed their test.")
This code, for example, skips the line that starts with the hashtag.
When you’re writing a program, you may want to test a specific block of code to make sure that it works before the rest of your program runs. In Python, you can use try/except blocks to test your code for problems and handle exceptions and errors gracefully.
Here is the syntax for a try/except operation:
try: print(ourVariable) except: print('Error returned')
sorted() function allows you to sort a list. For example, you can use
sorted() to sort an array of employee names in ascending order, or a list of orders in descending order of their order IDs. Here’s the syntax for the Python
data = [9, 12, 8, 4, 6] sortedData = sorted(data) print(sortedData)
You can use sort to arrange a list in both ascending or descending order. Or you can use the
key parameter to specify your own custom sort if you want to run a more advanced sort operation on your list of values.
Python Queue and Deque
Queues are a function in Python that allows you to store data in a first-in, first-out order. For example, if you have a product waitlist and want to enable people to order your product in order of when they signed up, you could use a queue.
Here is the syntax for a Python queue:
from queue import Queue waitlist = Queue() waitlist.put('Erin') waitlist.put('Samantha')
This code would create a queue with two values: Erin and Samantha. You can also create a deque, which allows you to create a double-ended queue that is last-in, first-out. The syntax for this is as follows:
from collections import deque waitlist = deque() waitlist.append('Erin') waitlist.append('Samantha')
Arrays are an essential data type in Python that allows you to store lists of data. For example, you could use an array to store a list of car names, or a list of flavors an ice cream store sells. Arrays are declared like so:
students = ['Alex', 'Bill', 'Catherine', 'Andy', 'Molly', 'Rose']
You can manipulate arrays in several ways: you can add items, remove items, clear the array, and more. Learn more about Python array functions in our guide on the topic here.
When you’re writing a program, you may want to print a value to the console and keep it on the same line as another value. For example, you may wish to an employee’s name, payroll address, and salary to appear on the same line in your program.
The syntax for printing without a new line in Python 3 is as follows:
print("Hello there!", end = '') print("It is a great day.")
Here’s the syntax for printing a statement without a new line in Python 2.x:
print "Hello there!", print "It is a great day."
There may be an occasion where you have a list that you want to flip into reverse order. For example, you may have a list of employee names in alphabetical order that you want to appear in reverse alphabetical order.
There are three ways you can reverse a list in Python:
You can find out more about how these methods work in our guide on the topic.
Python Append to List
When you’re working with a list, you may want to add items to that list. For instance, you may have a list of toy animals stocked at a store to which you want to add a new animal.
We can use three functions to append an item to a list:
Append() allows you to add an item to the end of a list.
Insert() will enable you to add an item at a specific position in a list.
Extend() allows you to merge two lists into one. Read our guide on these methods for examples on how to use them in practice.
We can use a Python
break statement to stop a loop and continue with the rest of a program, and the
continue statement works to exit a loop and proceed to the next iteration. Both of these statements are useful if you’re looking to skip certain parts of a loop.
Here’s an example of the break statement in action:
students = ["Paul", "Erin", "Connie", "Moira"] for student in range(0, len(students)): if student == 2: break print(students[student]) print("Counter is " + str(student)) print("Program Complete")
This code will stop our loop when
student is equal to
2. In addition, the
continue statement uses the same syntax as the
break statement above. Thus, we could replace
continue if we just wanted to skip printing a student’s name when
student is equal to
Often, you’ll store data for a Python program in a file, which is useful if you have large sets of data you want to work with, or if you want to save data. To read the contents of a file, there are three Python functions that you can use:
read(): Returns the contents of a file
readline(): Returns the next line of a file
readlines(): Returns a list of lines in a file
Read our full guide on Python read file methods to learn more about how these work, and how you can use them to read the contents of a file.
Python is a programming language that works in a variety of ways. You can use Python to create web applications, or to analyze data, or to run a simple program. In this guide, we have broken down a number of the most common Python operations for beginners. We’ve discussed everything from how to create a substring, to how to use an array in Python.
As you embark on your journey to mastering Python, feel free to keep coming back to this handbook and use it as a resource to help guide your next steps. We will update this guide as we write more articles so that it’s easy for you to find the information you need to learn Python as a beginner. After following this guide, you’ll be ready to handle several common operations in Python.