Loops & Lists — From Variables to Student Records

Learning Objectives

• Iterate with for loops using range() and direct iteration over sequences.
• Create and manipulate Python lists: indexing, slicing, len(), append, insert, remove, pop.
• Recognize the limitations of “one-variable-per-student” and refactor to list-based structures.
• Use parallel lists (e.g., names, surnames, grades) and iterate over them (with range or zip).

Session Plan (theory)

1. Motivation: the scaling problem
   • Naive approach:

     name1 = "Ali"; surname1 = "Yılmaz"; grade1 = 86
     name2 = "Ayşe"; surname2 = "Demir"; grade2 = 92
     # … quickly becomes unmanageable as student count grows
     

   • Why this doesn’t scale; benefits of sequences.
2. for loops
   • Iterating with for x in sequence: vs for i in range(n):.
   • Off-by-one pitfalls; range(start, stop, step).
3. Lists
   • Creating lists; indexing & slicing; len().
   • Adding/removing items: append, insert, remove, pop.
   • Iterating over values and over indices; using zip for parallel lists.
4. Parallel lists for simple records
   • names = [...], surnames = [...], grades = [...].
   • Printing aligned rows; computing statistics (min, max, average).

Hands-on

• Mini Project: Student Registry v1 (Lists & Loops)
  • Start from an empty repo folder or continue last week’s.
  • Build three lists: names, surnames, grades (seed a few entries).
  • Tasks:
    1. Print all students as # index - Full Name - Grade.
    2. Compute class size, average grade, best/worst grade (show name + value).
    3. Add a new student (append to each list) and reprint the table.
    4. Remove a student by index (use pop) and reprint.
    5. Bonus: use zip(names, surnames, grades) to print full rows without indices.