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DSA Interview Prep · Lesson

Lists, Tuples, and Slicing

Master Python list operations, slicing syntax, and tuple immutability with hands-on examples drawn from classic coding challenges.

Python Lists: Dynamic Arrays

A Python list is a dynamic array that holds anything and grows on its own. It is ordered, changeable, and gives you instant O(1) access by index. The code shows the basics.

nums = [3, 1, 4, 1, 5]
print(nums[0])   # 3
print(nums[-1])  # 5  (last element)
nums.append(9)
print(len(nums)) # 6

Common List Operations

Know these by heart: append and pop at the end are O(1), but insert at the front is O(n). Avoid remove in tight loops — it rescans every time.

stack = []
stack.append(1)
stack.append(2)
stack.append(3)
print(stack.pop())   # 3  O(1)
print(stack)         # [1, 2]

# insert at index 0 is O(n)
stack.insert(0, 0)
print(stack)         # [0, 1, 2]

All lessons in this course

  1. Lists, Tuples, and Slicing
  2. Dictionaries and Sets in Python
  3. Comprehensions and Built-ins
  4. Functions, Closures, and Lambda
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