• A variable is a name bound to a value.
• Assignment uses = (not equality).
• Python is dynamically typed — the type is inferred from the value.
• Multiple assignment and swapping are concise.

x = 42           # int
name = "Alice"   # str
pi = 3.14159     # float
active = True    # bool

# Multiple assignment
a, b, c = 1, 2, 3

# Swap without a temp variable
a, b = b, a

# Augmented assignment
x += 10   # same as x = x + 10

Arithmetic

Op	Meaning	Example
+ - * /	Basic	5 / 2 → 2.5
//	Floor division	5 // 2 → 2
%	Modulus	5 % 2 → 1
**	Exponent	2 ** 8 → 256

Comparison

==, !=, <, >, <=, >= → returns True/False

Logical

x = 5
print(x > 0 and x < 10)  # True
print(x < 0 or x > 3)    # True
print(not x == 5)         # False

Short-circuit evaluation

and stops at the first False.
or stops at the first True.

data = None
result = data or []   # [] if data is falsy

Type	Example	Notes
int	42, -7	Unlimited precision
float	3.14, 1e-6	IEEE 754 double
complex	2+3j	j for imaginary unit

print(type(42))      # <class 'int'>
print(type(3.14))    # <class 'float'>
print(10 / 3)        # 3.3333...
print(10 // 3)       # 3

Type Conversion

int("42")        # 42
float("3.14")    # 3.14
str(100)         # '100'
bool(0)          # False
bool("hello")    # True

• Immutable sequences of Unicode characters.
• Single, double, or triple quotes.
• Indexing (s[0]) and slicing (s[1:4]).
• Rich method library: .upper(), .split(), .strip(), .replace(), …

s = "Hello, World!"
print(s[0])        # H
print(s[-1])       # !
print(s[7:12])     # World
print(s.lower())   # hello, world!
print(s.split(",")) # ['Hello', ' World!']
print(len(s))      # 13