Python Output & Comments

print() is how your program talks to you, and comments are how you talk to the next person who reads your code. Both look simple, but a few options make them far more useful.

The print() function

print() writes text to the screen and then moves to a new line. You can give it any value: text, numbers, lists or the result of a calculation.

print("Hello, Python")print(42)print(3.5 * 2)print([1, 2, 3])print()                 # an empty lineprint("after the blank line")

Hello, Python
42
7.0
[1, 2, 3]

after the blank line

Print several values

Separate values with commas. print() converts each one to text and puts a space between them, so you can mix text and numbers without converting anything.

name = "Asha"tests = 12print("Tester:", name, "ran", tests, "tests")

Tester: Asha ran 12 tests

Change the separator: sep

sep sets what goes between the values. The default is a single space.

print("2026", "11", "02", sep="-")print("a", "b", "c", sep="")print("login", "search", "checkout", sep=" | ")

2026-11-02
abc
login | search | checkout

Change the line ending: end

end sets what is printed after the last value. The default is a newline ("\n"), so each print() starts a new line. Change it to keep printing on the same line.

for step in range(1, 4):    print("step", step, end=" -> ")print("finished")

step 1 -> step 2 -> step 3 -> finished

Print variables with f-strings

An f-string starts with f before the quote. Anything in { } is replaced by its value. This is the clearest way to build output.

item = "keyboard"price = 1499.5qty = 2print(f"{qty} x {item} = {price * qty}")print(f"Price with 2 decimals: {price:.2f}")print(f"{qty=}")

2 x keyboard = 2999.0
Price with 2 decimals: 1499.50
qty=2

Escape characters

A backslash inside a string starts an escape sequence:

print("Name\tScore")print("Asha\t91")print("Line one\nLine two")print("She said \"hi\"")print("C:\\tests\\report.txt")

Name	Score
Asha	91
Line one
Line two
She said "hi"
C:\tests\report.txt

Print to a file

print() can write to a file instead of the screen with the file argument. The File Handling lesson explains open() in detail.

with open("log.txt", "w") as log:    print("test started", file=log)    print("test passed", file=log) print(open("log.txt").read())

test started
test passed

Comments

A comment starts with #. Python ignores everything from # to the end of the line. Use comments to explain why the code does something, not what it obviously does.

# Prices are stored in paise to avoid rounding errors with floatsprice_paise = 149950 discount = 0.10   # 10% festival discount, ends 15 Novfinal = price_paise * (1 - discount)print(final / 100)

1349.55

Multi-line comments

Python has no special multi-line comment. Put # at the start of each line. Most editors do this for a selection with Ctrl+/.

# Step 1: read the users file# Step 2: keep only active users# Step 3: print their namesusers = [("asha", True), ("ravi", False), ("meena", True)]print([name for name, active in users if active])

['asha', 'meena']

Docstrings

A string written as the first line of a function, class or module is a docstring. Unlike a comment, Python keeps it, and help() shows it.

def area(width, height):    """Return the area of a rectangle."""    return width * height print(area(3, 4))print(area.__doc__)

12
Return the area of a rectangle.

Check your understanding

print("a", "b", sep="*", end="!")print("c")

a*b!c

item = "Mouse", qty = 3, price = 349.5

Mouse | 3 | 1048.50

item = "Mouse"qty = 3price = 349.5print(item, qty, f"{qty * price:.2f}", sep=" | ")

Mouse | 3 | 1048.50

Program Practice

Python print and comments FAQ