Python Cheat Sheet
Python Basics: A Quick Guide
Python is a popular and a high-level programming language that is widely used for web development, data analysis, artificial intelligence, and many other applications. It was first released in 1991 by Guido van Rossum, and since then it has become one of the most popular programming languages in the world..
Python is a very powerful programming language and is commonly used in a wide range of applications. Here are some of the most popular areas where Python is used: Data Analysis and Visualization, Web Development, Scientific Computing and Education.
If you’re new to Python, this quick guide will introduce you to some of the basics. Here are a few essential Python commands to get you started:
VARIABLES AND TYPES
In Python, variables are used to store values, such as numbers, text, or objects, that can be used later in your code. Each variable has a name and a value, and you can change the value of a variable throughout your program. Python has several built-in data types, including: Numbers, Strings, Lists, Tuples, Dictionaries and Sets.
Example:
# Assigning values to variables
x = 5
name = "Alice"
numbers = [1, 2, 3, 4, 5]
# Checking the types of variables
print(type(x)) # Output:<'int'>
print(type(name)) # Output: <'str'>
print(type(numbers)) # Output: <'list'>
LISTS
In Python, lists are used to store collections of items, such as a list of names, numbers, or any other data type. They are one of the most commonly used data types in Python and are extremely versatile. Lists are mutable, meaning you can change their contents by adding, removing, or modifying items.
# Creating a list
fruits = ['apple', 'banana', 'cherry']
#Adding an item to the list
fruits.append('orange')
# Removing an item from the list
fruits.remove('banana')
# Accessing items in the list
print(fruits[0]) # Output: apple
print(fruits[2]) # Output: cherry
LOOPS
Loops are used in Python to repeat a block of code multiple times. They are an essential part of programming and can be used in many different ways, such as: Iterating over a list, Repeating a block of code until a certain condition is met, Generating a sequence of numbers or values and Parsing and manipulating text or data. There are two types of loops in Python: for loops and while loops.
Example:
# Using a for loop to iterate over a list
fruits = ['apple', 'banana', 'cherry']
for fruit in fruits:
print(fruit)
# Using a while loop to repeat a block of code until a condition is met
i = 0
while i < 10:
print(i)
i += 1
DICTIONARIES
In Python, dictionaries are used to store key-value pairs, which allow you to quickly retrieve values by their associated key. They are enclosed in curly braces and each key-value pair is separated by a colon. Dictionaries are extremely useful when you need to store and retrieve values based on a specific key. They are commonly used in web development to represent data, such as user information or configuration settings.
# Creating a dictionary
person = {'name': 'Alice', 'age': 25, 'city': 'New York'}
# Accessing values in a dictionary
print(person['name']) # Output: Alice
print(person['age']) # Output: 25
# Adding a new key-value pair to the dictionary
person['occupation'] = 'Engineer'
# Removing a key-value pair from the dictionary
del person['city']
CONDITIONAL STATEMENTS
In Python, conditional statements are used to execute different blocks of code depending on whether a certain condition is true or false. The most commonly used conditional statements in Python are if, else, and elif (short for “else if”). Conditional statements are an important part of programming and allow you to make decisions based on certain conditions. They are commonly used in many different applications, such as data analysis, web development, and game programming.
# Using an if statement to execute code based on a condition
x = 10
if x > 5:
print("x is greater than 5")
else:
print("x is less than or equal to 5")
These are just a few examples of some of the basic concepts in Python. By mastering these concepts, you can start building more complex programs and applications in Python.
IN CONLUSION
Python is a popular high-level programming language that is known for its simplicity and versatility. It is used in many different applications, from data analysis and machine learning to web development and game programming.
Python provides a variety of built-in data types and control structures, such as variables, lists, loops, dictionaries, and conditional statements, which allow you to write powerful and flexible code. By mastering these fundamental concepts, you can become a proficient Python programmer and create your own applications and tools.