Nested Loops in Python

A single for loop handles one sequence. Place one loop inside another, and you can work with rows and columns, generate every combination from two lists, and build useful tables and repeating patterns. This Block explains outer and inner loops step by step, with a clear focus on tracing execution and predicting how many times the inner body runs.

What you will learn:

• Identify the outer loop, inner loop, and the code owned by each one
• Trace how the inner loop restarts for every outer-loop iteration
• Calculate total iterations for simple nested loops
• Create every possible pair from two lists
• Build grids, text patterns, and a multiplication table with an accumulator
• Use break and continue inside nested loops without losing track of which loop they affect
• Avoid common mistakes with indentation, loop variables, and accumulator placement

Finish with a practical mental model for reading nested loops one outer value and one complete inner pass at a time.