This is a Python cheat sheet for beginners to give a quick and easy introduction to the basic syntax of Python.

The version of Python I am using for this Python cheat sheet is Python 3.

I will be constantly adding more concepts to this Python cheat sheet over time. But for now, let’s just start with the basics.

Click here to skip to the Python cheat sheet section.

Why Python?

When starting out on learning how to program, more or less, we all feel overwhelmed about which programming language we should start with.

In terms of my personal experience, I was looking for a programming language that is easy to understand as a beginner. Not only that, but I was also making sure that there is a huge demand for that particular programming language in the world of software development.

And fortunately, I found the programming language that I wanted to start my development career with. It was Python!

Here are also three reasons why Python why I think Python is the best programming language for beginners.

Python is Easy to Learn

Perhaps one of the reasons why Python is the best programming language for beginners is that it is easy to learn. Compared to other programming languages, syntaxes in Python are quite simple and beginner-friendly.

As a result, Python has become the most popular introductory teaching language at the top U.S. universities.

To make this concept clear, let’s write a simple “Hello World” program in Java. Then I will write the same program in Python as well.

“Hello World” in Java:

public class HelloWorld {

    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Now let’s write the same program in Python:

print("Hello World!")

Yes, I know. It’s that simple in Python!

Although Python is a beginner-friendly language, it is very powerful and scalable. Python is widely used in different sectors such as Artificial Intelligence, Data Science, Network Programming, etc.

Check out the ultimate getting started guide on learning how to code.

A Huge Community Dedicated to Python.

We all know that to learn a new skill, it takes time. Furthermore, a lot of dedication and practice.

And during the learning process, it is usual to get stuck at a problem or a topic. The hard truth is, you won’t be able to understand all the concepts right off the back.

But fear not. For all your questions, concerns, and confusion there are huge communities over the internet ready to answer your question.

Here is the list of communities where you can find help from.

a) StackOverflow
b) GitHub
c) Reddit
d) Quora

And of course, there are many more.

Due to an immense amount of support from these communities, Python is probably the best programming language for beginners starting out with software development.

Libraries, Modules & Frameworks

When it comes to Python, there is a massive number of open source libraries, modules, and frameworks.

Think of these as reusable codes that are written by other programmers to make your life easier. And all these codes can be integrated into your Python program based on your needs and requirements.

One of the most popular libraries for Python is the Python Standard Library.

Other than that, Django and Flask are two of Python’s web development frameworks to build large-scale web applications using Python.

Moreover, some of Python’s machine learning libraries are Numpy, Pandas, Scipy, Scikit-learn, TensorFlow (My Fav!), etc.

The availability of all the libraries, modules, and frameworks, is another reason why Python is the best programming language for beginners.

The Python Cheat Sheet

You can also use these code snippets as references in the future. We will start from the very basic print function and make our way all the to classes and objects.

print() Function

First of all, let’s start with one of the most basic Python functions which print().

The print() function is a function that prints out messages onto the screen.

print("Hello world.")

Numbers & Arithmetic Operators

a = 1     # Integer
b = .5    # Float

>>> 2 + 3
5

>>> 5 * 3
15

>>> 1 / 2
0.5

We use a double asterisk to denote exponential operations.

>>>  2 ** 3 
8

The percent symbol denotes modulo. The Python modulo is an operation to find the remainder of a division.

>>> 2 % 2
0

>>> 5 % 2
1

Also, the mathematical rule of precedence applies to Python.

>>> (2 + 3)  *  (5 + 5) 
50

Variables

Think of variables as containers to store values. In short, when you create a variable you are reserving some space in the computer’s memory to store particular values.

Additionally, a variable cannot start with a number of special characters.

variableName = 2
x = 10
y = 15

result = x + y

You can also use the print() function to print the variable.

print(result)

Strings

Strings are a sequence of characters, within single or double quotations.

'hello world' # single quotations
"hello world" # double quotations 

Assigning a string to a variable.

var = "hello world"

Lists

A list in Python is a data type that holds multiple values separated by commas. Also, you write a list within square brackets.

[1,2,3,5,6,7,8,9,10]

You can store strings inside a list as well. Even more, you can nest a list inside another list as well.

['hi',1,[1,2]]

To append something at the end of the list, use the append() function.

listOfChars = ['a','b','c','d','e','f']
listOfChars.append('g')

For instance, slicing a character at index 0 from a list.

listOfChars[0]

Slicing a character at index 1 from a list.

listOfChars[1]

Slicing everything, starting from index 1 till the last index of the list.

listOfChars[1:]

Slicing from index 0 till index 1. Note that here Python will not slice the index after the colon.

listOfChars[:1]

Adding a string at the index position 0 of our list.

listOfChars[0] = 'New String'

Furthermore, a list can also have nested lists.

nestedList = [1,2,3,[4,5,['nested']]]
nestedList[3]
nestedList[3][2]
nestedList[3][2][0] 

Dictionaries

A dictionary in Python is a collection of key-value pairs within curly brackets.

dic = {'key1':'value1','key2':'value2'}

We can access the values of a dictionary by calling its corresponding key name, inside square brackets.

Booleans

In short, booleans are data types consisting of True & False values only.

True
False

Tuples

Tuples are an immutable and unchangeable collection of elements surrounded by parentheses.

We can access tuple elements by referring to the index number, inside square brackets.

t[0]

In contrast to lists, tuples are immutable. As a result, they can’t be changed after you have already assigned values to them.

For example, the statement below will display an error message since we can’t change the tuple.

t[0] = 'new value'

Sets

Sets in Python are a collection of elements that have no order and neither any index. So, we cannot access sets by referring to their index positions.

Sets are written within curly brackets.

>>> {1,2,3}
>>> {1,2,3,1,2,1,2,3,3,3,3,2,2,2,1,1,2,3,2,2,2,3,3,1,1,1,3,2}
{1,2,3}

Comparison Operators

Comparison operators in Python are used to compare two values.

>>> 1  >  3
False

>>> 1  <  3
True

>>> 1 <= 2
True

>>> 2 >= 2
True

>>> 1 == 1
True

>>> 'come' == 'go'
False 

Logical Operators

Just as comparison operators, Python has logical operators as well.

Logical operators in Python are AND, OR and NOT. Therefore, they are used with conditional statements to perform boolean operations.

>>> (1 > 2) and (2 < 3)
False

>>> (1 > 2) or (2 < 3)
True

>>> (1 == 2) or (2 == 3) or (4 == 4)
True

if,elif, else Statements

These are conditional statements, used for performing different actions based on different conditions.

The following example utilizes the comparison operators that we talked about before.

if 1 < 2:
     print('One is less than two!')

if 1 < 2:
     print(1)
else:
     print(2)

if 1 > 2:
     print(1)
else:
     print(2)
 
if 1 == 2:
     print(1)
elif 3 == 3:
     print(3)
else:
     print('Nothing to show!')

for Loops

In Python, you use for loop to iterate over a sequence such as a list, dictionary, tuple, string, or set.

num = [1,2,3,4,5]
for i in num:
     print(i)

for i in num:
     print('It works!')

while Loops

Also, if the condition is False, then the while loop will go on infinitely.

i = 1 
while i < 5:
    print('i is: {}'.format(i))
    i = i+1

range() Function

range() is a function that returns a sequence of numbers.

To clarify, the statement below tells Python to generate a sequence of 5 numbers starting from 0 to 5.

range(0,5)

To display the range of values, we need to use a for loop.

for i in range(2,10):
     print(i)

List Comprehension

List comprehension is a way to create a new list from other iterable data types such as list, tuples, etc.

out = []
for item in x:
     out.append(item**2)
 print(out)

Here’s another example of list comprehension in Python.

[item**2 for item in x]

Functions

Functions are code blocks that you can call in your program. Hence, they are highly useful if you need to perform a repetitive task.

Rather, writing the same code over and over again, you can call a function.

def newFunction(param):
 print(param)

newFunction('Nice.')

Furthermore, here’s a function that returns a value.

def square(x):
     return x**2

result = square(4)
print(result)

Lambda Functions

A lambda function is a function that has only one line of expression. Therefore, they are useful when it comes to creating small and one-line function expressions.

To demonstrate, here’s a regular function.

def timesTwo(var):
     return var*2

print(timesTwo(2))

Now, here is a lambda function.

lambdaFunction = lambda var: var*2
print(lambdaFunction(2))

Classes

Class is a “blueprint” or a template for creating objects in Python. Remember that Python is an Object Oriented Programming language.

A class consists of properties and behavior. In other words, attributes and methods.

A method is a function that is called on an object of a class.

class Car():

 def init(self, name):
  self.name = name

 def accelerate(self):
  print(self.name + " is accelerating!.") 


myCar = Car('Audi R8')
print(myCar.name + " is a great car!")
myCar.accelerate() 

Conclusion

If you can think of any concepts that you want me to add to this Python cheat sheet, feel free to comment below.

And when I started coding, working with Python was not just simple but also fun. Thus, this always motivated me to learn and practice more.

If you are still wondering what programming language you should start learning first, then go with Python.

To help you out, here’s where you can get started today:

Udacity is an online educational platform that offers industry-recognized nanodegree programs on programming, web development, artificial intelligence, etc.

They have free online Python courses designed for absolute beginners who have never programmed before.

I highly recommend that you check out their Programming Foundations with Python course. This is a free introductory course for beginners that will teach you the basics of Python and object-oriented programming.

Also, check out their Introduction to Programming nanodegree program to give yourself a great start towards careers in Web and App Development, Machine Learning, Data Science, AI, and more.

I am confident enough that learning to code with Python will not just be fun but a rewarding experience at the same time.

What other concepts do you think I should add to this Python cheat sheet for beginners?