Index Characters without Losing the First One
Label characters from index 0 and select the stated position.
About 18 minutes, plus any extended practice
Open lesson 1Build Programs with Text and Lists
For text="planet" and values=[4,8,3], find text[1:4],values[1] and len(values). Explain the excluded slice endpoint.
Before you begin
- Read short literal code and number positions from zero.
Choose by skill rather than age alone. Read with an adult when useful, revisit a lesson, or explore another grade.
Follow the lesson sequence
Slice a Stated Segment of Text
Include the start index and stop before the stated stop index.
About 18 minutes, plus any extended practice
Open lesson 2Select a List Item by Position
Number list positions from 0 and return the value at the stated index.
About 18 minutes, plus any extended practice
Open lesson 3Measure a Collection with len
Count the elements directly inside the outer sequence.
About 18 minutes, plus any extended practice
Open lesson 4Review and transfer
After the lessons, try 4 new review cases and a practical task. Each answer has an explanation and a link back to the related lesson.
Open the unit reviewGuest answers are temporary. Keep your own paper or document; this unit does not certify completion or record a school grade.
Topic references
- 2026 CSTA PK–12 Computer Science Standards: topic reference — Programming; Data & Analysis
These references informed the topic selection. They do not certify complete standards alignment.