PythonReturn Values

Return Values in Python Functions

In Python, a function can send back a value to the part of the program that called it. This is done using the return statement.

Functions that return values are more flexible because the caller can use the result in further calculations or logic.

Basic Syntax of return

return_syntax.py
def function_name():
    return value
  • return ends the function and sends a value back to the caller.
  • If no return is used, the function returns None by default.

Example 1: Returning a Single Value

return_single.py
def add(a, b):
    return a + b
 
result = add(3, 5)
print("Sum is:", result)
output.txt
Sum is: 8

Explanation:

  • The function returns the result of a + b.
  • The caller stores this value in result.

Example 2: Returning a String

return_string.py
def greet(name):
    return f"Hello, {name}"
 
message = greet("Alice")
print(message)
output.txt
Hello, Alice

Explanation:

  • The function builds a string and returns it.
  • The caller receives and prints the string.

Example 3: Returning Multiple Values (Tuple)

return_multiple.py
def get_stats(numbers):
    return min(numbers), max(numbers), sum(numbers)
 
low, high, total = get_stats([4, 7, 1, 9])
print("Min:", low)
print("Max:", high)
print("Sum:", total)
output.txt
Min: 1
Max: 9
Sum: 21

Explanation:

  • A function can return multiple values as a tuple.
  • The caller can unpack the values.

Example 4: Returning a List

return_list.py
def squares(n):
    return [i * i for i in range(1, n + 1)]
 
print("Squares:", squares(5))
output.txt
Squares: [1, 4, 9, 16, 25]

Explanation:

  • The function returns a list of computed values.

Example 5: Returning a Dictionary

return_dict.py
def person_info(name, age):
    return {"name": name, "age": age}
 
info = person_info("John", 30)
print(info)
output.txt
{'name': 'John', 'age': 30}

Explanation:

  • The function returns a dictionary of key-value pairs.

Example 6: Returning None

return_none.py
def log_message(message):
    print("LOG:", message)
 
result = log_message("Processing started")
print(result)
output.txt
LOG: Processing started
None

Explanation:

  • If a function does not return anything, Python returns None.
  • Useful for side-effect functions (logging, writing to file, etc.).

Why Use Return Values?

ReasonBenefit
Reuse resultsValue can be passed around your program
Flexible function behaviorDifferent callers can use the result differently
Separate calculation from displayFunctions focus on computing, not printing
Compose multiple functionsFunctions can call each other and build pipelines

Summary

  • The return statement sends back values from a function.
  • You can return any type: string, int, float, list, tuple, dict, None.
  • Functions can return multiple values.
  • Returning values allows your code to be modular, flexible, and reusable.

In the next section, we will explore Variable Scope — understanding where variables live and how long they last inside your functions and programs.

Arguments and ParametersVariable Scope