➗ Python Basics

Operators & Expressions

ऑपरेटर और एक्सप्रेशन

⏱ 2 hr3 topicsInteractive

🎯 By the end: You can use every category of Python operator correctly, predict the result of an expression, and tell apart / , // and %.

Operators are the verbs of programming — they do things to values: add them, compare them, combine conditions. Python has several families of operators, and this chapter runs through all of them with a playground so you can test every result yourself.

1Arithmetic operators

These do maths. Three of them surprise beginners, so look closely:

Operator	Meaning	Example	Result
`+` `-` `*`	add, subtract, multiply	`7 * 2`	14
`/`	division — always gives a float	`7 / 2`	3.5
`//`	floor division — drops the fraction	`7 // 2`	3
`%`	modulo — the remainder	`7 % 2`	1
`**`	exponent (power)	`2 ** 3`	8

The % (modulo) operator is a workhorse: n % 2 == 0 tests if n is even, and it's everywhere in real programs. Run the playground and change the numbers to feel how /, // and % differ.

Arithmetic operators▶ runs real Python

main.py

print(7 + 2)    # 9
print(7 / 2)    # 3.5  division is always a float
print(7 // 2)   # 3    floor division
print(7 % 2)    # 1    remainder (modulo)
print(2 ** 3)   # 8    power

Output

Click Run to execute.

Key points

/ always gives a float (7/2 = 3.5); // is floor division (7//2 = 3).
% (modulo) gives the remainder; n % 2 == 0 tests for even numbers.
** is exponent (2**3 = 8).

2Comparison and logical operators

Comparison (relational) operators compare two values and always produce a Boolean — True or False:

Operator	Meaning
`==`	equal to
`!=`	not equal to
`<` `>`	less than, greater than
`<=` `>=`	less than or equal, greater than or equal

Don't confuse = (assignment — put a value into a variable) with == (comparison — ask if two values are equal). Mixing them up is a classic bug.

Logical operators combine Boolean values:

and — True only if both sides are True.
or — True if either side is True.
not — flips True to False and vice versa.

Comparison & logical operators▶ runs real Python

main.py

print(5 > 3)            # True
print(5 == 5)           # True
print(5 != 3)           # True
print(3 <= 2)           # False
print(5 > 3 and 2 > 4)  # False (and needs both True)
print(5 > 3 or 2 > 4)   # True  (or needs either)

Output

Click Run to execute.

Key points

Comparison operators (==, !=, <, >, <=, >=) always return a Boolean (True/False).
= assigns a value; == checks equality — don't confuse them.
Logical: and needs both True, or needs either True, not flips the Boolean.

3Assignment, identity and membership

Three more handy families:

Assignment: = stores a value. The shortcuts +=, -=, *=, /= update a variable in place — x += 5 means x = x + 5.
Membership: in and not in test whether a value appears inside a string, list, etc. — 'a' in 'cat' is True.
Identity: is and is not test whether two names refer to the same object in memory (not just equal values). It's most commonly used as x is None.

Operator precedence decides the order: ** first, then * / // %, then + -, then comparisons, then not, and, or. When in doubt, use parentheses to make the order explicit and readable.

Assignment & membership▶ runs real Python

main.py

score = 10
score += 5        # same as score = score + 5
print(score)      # 15

print('a' in 'cat')       # True
print('z' not in 'cat')   # True

Output

Click Run to execute.

Key points

= assigns; shortcuts like += update in place (x += 5 means x = x + 5).
Membership in / not in test if a value is inside a string/list.
Identity is / is not test if two names are the same object (often x is None).
Precedence: ** then * / // % then + - then comparisons then not/and/or; use parentheses to be clear.

★ Practical: predict, then run

First predict each result on paper, then check it in the playground:

What do 17 / 5, 17 // 5 and 17 % 5 each give?
Is 4 == 4.0 True or False? What about 4 is 4.0?
Evaluate: (3 > 2) and (5 != 5).
Start with x = 8, then do x *= 2 twice. What is x?

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