Chapter 03 · foundation · runs in browser
Lists and maps
Read structured data, access items safely, and test whether values are present.
01Lists and indexesSelect an item from a list and see what an invalid index does.Try CEL02Maps and member accessRead values with dot notation and square brackets.Try CEL03Membership and collection sizeTest whether a value is in a list and check the number of items.Try CEL04Presence, null, and missing valuesCheck that a member is present before trying to read its value.Try CEL