Calling functions ¶

After you define a function, you can use (or "call") it by writing its name followed by parentheses. If the function needs inputs, you provide them inside the parentheses.

In [ ]:

# Defining the functions
def say_hello():
    print("Hello!")

def greet(name):
    print(f"Hello, {name}!")

# Calling the functions
say_hello()          # Prints: Hello!
greet("Alice")       # Prints: Hello, Alice!

# Defining the functions def say_hello(): print("Hello!") def greet(name): print(f"Hello, {name}!") # Calling the functions say_hello() # Prints: Hello! greet("Alice") # Prints: Hello, Alice!

Working with Return Values ¶

When a function returns a value, you can:

• Store it in a variable
• Use it directly in calculations
• Pass it to other functions

In [9]:

def double(number):
    return number * 2

# Store the result
result = double(5)

# Use in calculation
total = double(3) + double(4)

# Pass to another function
print(double(6))

def double(number): return number * 2 # Store the result result = double(5) # Use in calculation total = double(3) + double(4) # Pass to another function print(double(6))

12

Providing Arguments ¶

When calling a function, you need to provide the right number of arguments (inputs):

def calculate_area(length, width):
    return length * width

# ✅ Correct: Two arguments for two parameters
area = calculate_area(5, 3)      # area = 15

# ❌ Wrong: Too few arguments
area = calculate_area(5)         # Error!

# ❌ Wrong: Too many arguments
area = calculate_area(5, 3, 2)   # Error!

Using Variables as Arguments ¶

You can pass variables as arguments:

room_length = 10
room_width = 8

area = calculate_area(room_length, room_width)  # area = 80

Function Calls Inside Other Calls ¶

Functions can be nested:

def add_one(x):
    return x + 1

def multiply_by_two(x):
    return x * 2

# Nested function calls are evaluated from inside out
result = multiply_by_two(add_one(5))  # First 5+1=6, then 6*2=12