Looping through 1D arrays

Build the idea

Start with the concept and its key vocabulary.

Key idea

Traverse every 1D array element with correct ERL and Python loop bounds.

To visit every array element, use the loop counter as its index. ERL loops from 0 to array.length - 1 because to is inclusive. Python range(len(array)) naturally produces the same valid indices. Starting at 1 misses the first element; ending at length goes out of bounds.

Traversal

Visiting each item in a data structure in a systematic order.

Loop counter

The changing for-loop variable that can be used as an array index.

Linear search

Checking array values one by one in order until a target is found or the list ends.

Off-by-one error

Starting or ending a traversal one index too early or too late.

Keep these in mind

Use the same counter name inside the indexed expression.
ERL traversal is 0 to length - 1.
Python traversal by index is range(len(array)).
A Python loop written for item in values gives item values, not indices.

Build the idea

Start with the concept and its key vocabulary.

Key idea

Traverse every 1D array element with correct ERL and Python loop bounds.

Traversal

Visiting each item in a data structure in a systematic order.

Loop counter

The changing for-loop variable that can be used as an array index.

Linear search

Checking array values one by one in order until a target is found or the list ends.

Off-by-one error

Starting or ending a traversal one index too early or too late.

Keep these in mind

Use the same counter name inside the indexed expression.
ERL traversal is 0 to length - 1.
Python traversal by index is range(len(array)).
A Python loop written for item in values gives item values, not indices.