Variables and Assignment Statements

A variable is a named reference to a value stored in memory. Python variables do not need explicit type declaration — the type is determined at runtime (dynamic typing).

age = 20            # int
name = "Aditi"       # str
gpa = 8.7            # float
is_pass = True       # bool

Assignment Statement Forms

1. Simple assignment

x = 10

2. Multiple assignment (same value to many variables)

a = b = c = 100
print(a, b, c)   # 100 100 100

3. Multiple assignment (different values, one line)

x, y, z = 1, 2, 3
print(x, y, z)   # 1 2 3

4. Swapping values without a temp variable

a, b = 5, 10
a, b = b, a
print(a, b)      # 10 5

5. Augmented (compound) assignment

x = 10
x += 5    # x = x + 5  -> 15
x -= 2    # x = x - 2  -> 13
x *= 3    # x = x * 3  -> 39
x /= 2    # x = x / 2  -> 19.5

Rules

• Python variables are references to objects — assigning a new value rebinds the name; it does not overwrite memory in place for immutable types.
• type() can be used to inspect a variable's current type at any point.
• Variables can be re-declared with a different type at any time (dynamic typing).

value = 100
print(type(value))     # <class 'int'>
value = "one hundred"
print(type(value))     # <class 'str'>

id() — memory reference

a = 10
b = 10
print(id(a) == id(b))  # True — small ints are cached/interned by CPython