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What is Indentation and Why is it Important?

Indentation refers to spacing the beginning of a line of code to the right by a certain amount.

In most programming languages, indentation is encouraged to make the code look neat and organized. However, in Python, incorrect indentation can cause your program to throw errors, making it crucially important.


Code Blocks and Indentation​

In programming, a Code Block refers to a group of lines that are executed together.

Code blocks are mainly used in functions, conditionals, loops, etc., grouping logically related code for execution.

While many languages use curly braces { } to define code blocks, Python uses indentation.

Defining a function in JavaScript
// Function to add a and b
function add(a, b) {
    return a + b;
}
Defining a function in Python
# Function to add a and b
def add(a, b):
    return a + b

How to Use Indentation​

Indentation in Conditionals​

if, else statement
if condition:
    print("Executed if the condition is true")  # Indented
else:
    print("Executed if the condition is false") # Indented

In the example above, if the if condition is true, the indented print statement will execute.

If there's a mistake in indentation, the program will not function as intended.

Example of incorrect indentation
if condition:
# No indentation, error occurs
print("Executed if the condition is true.")

Indentation in Loops​

for loop iterating from 0 to 2
for i in range(3):
    print(i)  # Indented

In the example above, the for loop executes print statements for each value returned by range(3) from 0 to 2.

Without indentation on the print statement, the loop will not function correctly.

Example of incorrect indentation
for i in range(3):
print(i)  # No indentation, error occurs

Indentation in Functions​

Function to add two numbers
def add(a, b):
    result = a + b  # Indentation defines the function body
    return result   # Indentation specifies the return value

result = add(3, 5)

In the example above, the add function accepts two parameters (a, b) and returns their sum.

An argument is a value provided to a function to perform its task.

In the code, the function add receives 3 for a and 5 for b, and the variable result will store the returned value, which is 8.

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