Outer loop

Definition

The outer loop is the first or top-level loop in a nested loop structure. It controls the number of times the inner loop(s) execute.

5 Must Know Facts For Your Next Test

1. The outer loop runs a set number of times and for each iteration, it triggers the inner loop to execute fully.
2. Changes in the outer loop's control variable can affect the overall number of iterations of the nested loops.
3. In Python, both 'for' and 'while' loops can serve as outer loops.
4. Performance can be significantly impacted by how many times the outer loop iterates, especially if the inner loop has a high time complexity.
5. Outer loops are useful for tasks that require multi-level iteration, such as traversing a matrix or handling multiple dimensions in data structures.

Review Questions

• What is the role of an outer loop in a nested loop structure?
• How does modifying the control variable of an outer loop impact nested loops?
• Can both 'for' and 'while' loops be used as outer loops in Python?

Related terms

Inner Loop:

A loop that is contained within another loop (the outer loop). It executes completely every time its enclosing outer loop iterates once.

'For' Loop: 'For' loops iterate over a sequence (like list, tuple, dictionary, set, or string) with an explicit start and end condition.

'While' Loop: 'While' loops continue to execute as long as their condition remains true. They do not necessarily have a fixed number of iterations.