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Common Built-in Functions: len(), type(), range(), etc.

Following our exploration of Operator Precedence and Associativity, this article introduces some of Python's most common and useful built-in functions. These functions are always available to you, without the need to import any modules.

📚 Prerequisites​

A basic understanding of Python data types and variables.

🎯 Article Outline: What You'll Master​

In this article, you will learn:

  • ✅ How to use the len() function to find the length of an object.
  • ✅ How to use the type() function to determine the data type of a variable.
  • ✅ How to use the range() function to generate a sequence of numbers.
  • ✅ Other useful built-in functions.

🧠 Section 1: len() - Finding the Length​

The len() function returns the number of items in an object. It's commonly used with strings, lists, tuples, and dictionaries.

my_string = "Hello, World!"
print(len(my_string)) # Output: 13

my_list = [1, 2, 3, 4, 5]
print(len(my_list)) # Output: 5

💻 Section 2: type() - Checking the Data Type​

The type() function returns the data type of an object. This is useful for debugging and understanding your code.

my_string = "Hello, World!"
print(type(my_string)) # Output: <class 'str'>

my_integer = 10
print(type(my_integer)) # Output: <class 'int'>

🛠️ Section 3: range() - Generating a Sequence of Numbers​

The range() function generates a sequence of numbers. It's often used in for loops to repeat a block of code a specific number of times.

range(stop):

for i in range(5):
    print(i) # Output: 0, 1, 2, 3, 4

range(start, stop):

for i in range(2, 5):
    print(i) # Output: 2, 3, 4

range(start, stop, step):

for i in range(0, 10, 2):
    print(i) # Output: 0, 2, 4, 6, 8

🔬 Section 4: Other Useful Built-in Functions​

Here are a few other useful built-in functions:

  • abs(): Returns the absolute value of a number.
  • max(): Returns the largest item in an iterable.
  • min(): Returns the smallest item in an iterable.
  • sum(): Returns the sum of all items in an iterable.
  • round(): Rounds a number to a specified number of decimal places.

💡 Conclusion & Key Takeaways​

You've now learned about some of Python's most common built-in functions. These functions are powerful tools that will help you write more concise and efficient code.

Let's summarize the key takeaways:

  • len(): Returns the length of an object.
  • type(): Returns the data type of an object.
  • range(): Generates a sequence of numbers.
  • Other Functions: abs(), max(), min(), sum(), and round() are useful for working with numbers.

Challenge Yourself: Write a script that uses the range() function to print the numbers from 1 to 10, and then uses the sum() function to print the sum of those numbers.

➡️ Next Steps​

This article concludes our exploration of the absolute basics of Python. In the next series, we'll start learning about "Control Flow - Conditionals and Loops in Python".

Happy coding!

Glossary (Python Terms)​

  • Built-in Function: A function that is always available in Python, without the need to import any modules.
  • Iterable: An object that can be looped over, such as a string, list, or tuple.

Further Reading (Python Resources)​