Skip to content

Latest commit

 

History

History
120 lines (78 loc) · 3.39 KB

README.md

File metadata and controls

120 lines (78 loc) · 3.39 KB

Hello World

Objective

Write your very first Python program and understand what's happening when you run it.

Concepts Covered

  • The print() function
  • Strings (text in quotes)
  • How Python runs your code top-to-bottom
  • Comments

Prerequisites

  • None — this is the very beginning!

Lesson

Your First Line of Python

Every programming journey starts the same way — printing something to the screen. In Python, that looks like this:

print("Hello, World!")

That's it. One line. When you run this, Python will display:

Hello, World!

What's Actually Happening?

Let's break it down:

  • print is a built-in function. It tells Python "display this on the screen." You'll use it constantly.
  • ( and ) are parentheses. They wrap what you're passing to the function — this is called an "argument."
  • "Hello, World!" is a string — a piece of text. The quotes tell Python "this is text, not code." You can use either double quotes " or single quotes ' — both work the same way.

Printing Multiple Things

You can pass multiple items to print(), separated by commas. Python will add a space between each one:

print("Hello", "World")    # Output: Hello World
print("I", "love", "Python")  # Output: I love Python

Comments

See that # symbol? Anything after # on a line is a comment. Python ignores it completely — it's just a note for humans reading the code.

# This is a comment — Python skips this line entirely
print("This runs")  # Comments can go at the end of a line too

Use comments to explain why you're doing something, not what you're doing. The code itself should be clear enough to show what's happening.

Empty Lines and Whitespace

Python doesn't care about blank lines between statements. Use them to organize your code and make it readable:

print("Section 1")
print("Still section 1")

print("Section 2 — notice the blank line above for readability")

Special Characters in Strings

Sometimes you need to include characters that have special meaning. Use a backslash \ to "escape" them:

print("She said \"hello\"")   # Output: She said "hello"
print("Line 1\nLine 2")       # \n creates a new line
print("Tab\there")             # \t creates a tab

Or just use the other type of quote to avoid escaping:

print('She said "hello"')     # Single quotes outside, double inside
print("It's easy")            # Double quotes outside, single inside

The print() Function in Detail

print() has a few handy tricks:

# Change what goes between items (default is a space)
print("2025", "02", "09", sep="-")   # Output: 2025-02-09

# Change what goes at the end (default is a newline)
print("Loading", end="...")
print("Done!")                        # Output: Loading...Done!

# Print an empty line
print()

Code Example

Check out example.py for a complete working example that demonstrates everything above.

Exercises

Try the practice problems in exercises.py to test your understanding.

Key Takeaways

  • print() displays text on the screen
  • Strings are text wrapped in quotes (single or double — your choice)
  • Comments start with # and are ignored by Python
  • Python runs your code from top to bottom, one line at a time
  • print() supports sep and end parameters for formatting control