Introduction

Python is a strong language for DSA practice because the syntax stays small while the standard data structures stay powerful.

What matters most for DSA work

• Variables are dynamically typed.
• Lists, sets, dictionaries, and strings are built in.
• Indentation defines code blocks.
• Readability is a feature, not just style.

name = "Python"
year = 1991
is_good_for_dsa = True

print(name)
print(year)
print(is_good_for_dsa)
print(type(name), type(year), type(is_good_for_dsa))

Primitive values you will use often

count = 5              # int
ratio = 2.5            # float
title = "graph"        # str
active = False         # bool
nothing = None         # NoneType

print(count, ratio, title, active, nothing)

Mutability matters

Lists and dictionaries are mutable. Strings and tuples are not.

numbers = [1, 2, 3]
numbers[1] = 99

word = "stack"
updated = word.upper()

print(numbers)
print(word)
print(updated)

A small habit that helps

Name things after meaning, not after syntax.

• Better: left, right, window_sum, visited
• Worse: a, b, temp2, x1

That habit makes two-pointer, recursion, and graph code much easier to debug.