Chapter 3: Operators

Objectives

• Perform calculations with arithmetic operators.
• Compare values using comparison operators.
• Combine Boolean expressions with logical operators.
• Use simple and augmented assignment operators.
• Understand operator precedence and associativity.
• Explore identity (is) and membership (in) operators.

1. Arithmetic Operators

Basic mathematical operations:

2. Comparison Operators

Evaluate relationships; result is True or False:

3. Logical Operators

Combine Boolean expressions:

• and: True if both operands True
• or: True if at least one operand True
• not: invert a Boolean value

# Examples
True and False   # False
True or False    # True
not True         # False
      

4. Assignment & Augmented Assignment

Store and update variable values:

# Standard assignment
x = 10

# Augmented assignment
x += 5    # x = x + 5 → 15
x *= 2    # x = x * 2 → 30
x %= 7    # x = x % 7 → 2
      

5. Precedence & Other Operators

Order of operations (highest → lowest):

1. ** (exponentiation)
2. *, /, //, %
3. +, -
4. <, <=, >, >=
5. ==, !=
6. not
7. and
8. or

Identity & membership:

# Identity
a = [1,2,3]
b = a
c = a[:]
a is b    # True
a is c    # False

# Membership
2 in a    # True
5 not in a  # True
      

Exercises

1. Compute (3 + 5) * 2 ** 3 / 4 % 3, print each intermediate step.
2. Write a Boolean expression to check if n is strictly between 1 and 10.
3. Demonstrate difference between is and == with two identical lists.
4. Starting from x = 5, use augmented assignments to reach x = 120.