Python Refresher: Variables, Data Types, and Control Flow

Python Refresher

Even if you already know Python, a quick recap helps set the stage for data‑science‑specific code.

Variables and Data Types

# Numbers
x = 10          # int
y = 3.14        # float

# Strings
name = "Alice"

# Booleans
is_valid = True

# Collections
my_list = [1, 2, 3]
my_tuple = (1, 2, 3)
my_dict = {"id": 1, "value": 42}

Control Flow

# If‑else
if x > 5:
    print("big")
else:
    print("small")

# Loops
for i in range(5):
    print(i)

while x > 0:
    x -= 1

List comprehensions (the data‑science favorite)

squares = [i**2 for i in range(10)]