NotesPythonOperators & Strings

Operators

Arithmetic, comparison, logical, and assignment operators — the building blocks of every expression.

Arithmetic operators

print(7 + 3)    # 10  addition
print(7 - 3)    # 4   subtraction
print(7 * 3)    # 21  multiplication
print(7 / 3)    # 2.333...  true division, always returns a float
print(7 // 3)   # 2   floor division, rounds down to an int
print(7 % 3)    # 1   modulo, the remainder
print(7 ** 3)   # 343 exponentiation

// and % are a pair worth memorizing together: a == (a // b) * b + (a % b) always holds.

Comparison operators

==, !=, <, >, <=, >= compare values and always return a bool. Note == checks value equality, not identity — use is only when you specifically mean "the same object in memory" (most commonly x is None).

print(5 == 5.0)   # True  -- same value, different types, still equal
print([1, 2] == [1, 2])  # True -- lists compare element by element

Logical operators

and, or, not combine boolean expressions. Python short-circuits: a and b skips evaluating b if a is already falsy, and a or b skips b if a is already truthy.

subscribers = 250000
is_verified = True

if subscribers > 100000 and is_verified:
    print("Eligible for the Play Button")

Assignment operators

views = 100
views += 50   # same as views = views + 50
views *= 2    # same as views = views * 2
print(views)  # 300

Operator precedence

Python follows standard math precedence: ** first, then * / // %, then + -, then comparisons, then not, then and, then or. When in doubt, use parentheses — they cost nothing and remove ambiguity for whoever reads the code next.

Key points to remember
  • / always returns a float (true division); // floors the result to an int (floor division).
  • == compares values; is compares identity (same object) — use is only for things like x is None.
  • and/or short-circuit: the second operand is only evaluated if the first doesn't already decide the result.
  • a == (a // b) * b + (a % b) always holds — floor division and modulo are a matched pair.
  • When precedence gets unclear, add parentheses — it costs nothing and removes ambiguity.

Arithmetic and short-circuiting

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