Your First Python Program

Every program communicates. print() is Python's built-in way to send output to the screen — no imports, no setup, always available.

It's the first function every Python developer learns and the one they use most often: debugging, logging, showing results. Let's see what it can do.

print() is flexible. Give it one value, many values, or expressions:

print('Hello')              # Hello
print('Score:', 42)         # Score: 42
print(10 + 5)               # 15  ← expression evaluated first
print('a', 'b', 'c')       # a b c  ← values joined with space

Key insight: when you pass multiple arguments separated by commas, Python evaluates each one, then joins them with a space automatically.

Two optional parameters control print's output format:

# sep: what goes BETWEEN values (default: a space)
print('2024', '01', '15', sep='/')   # 2024/01/15
print('a', 'b', 'c', sep=' | ')      # a | b | c

# end: what goes AFTER all values (default: newline)
print('Loading', end='...')  # Loading...
print('done!')               # done!  ← continues right after
# Full output: Loading...done!

Comments are notes Python ignores completely:

# This entire line is a comment
birth_year = 1991        # inline comment
age = 2024 - birth_year  # 33

A good comment explains why a decision was made, not what the code does. The code already shows what it does.

# add 1 to x on x += 1 adds no value. # offset by 1 for 1-indexed display explains a non-obvious choice.