Create code to group a list of Contacts by their mailing state. The state keys should be uppercase, case-insensitive matching, and exclude contacts with null states.

Examples:

Input: contacts = [{FirstName: "John", LastName: "Doe", MailingState: "CA"}, {FirstName: "Jane", LastName: "Smith", MailingState: "ca"}, {FirstName: "Bob", LastName: "Johnson", MailingState: "NY"}] Output: {"CA" => ["John Doe", "Jane Smith"], "NY" => ["Bob Johnson"]} Input: contacts = [{FirstName: "John", LastName: "Doe", MailingState: null}, {FirstName: "Jane", LastName: "Smith", MailingState: "TX"}] Output: {"TX" => ["Jane Smith"]}
Apex Code Editor

Welcome to Lightning Challenge!

How It Works

  • • Write your solution in the code editor
  • • Connect your Salesforce org to test
  • • Submit to check if your solution passes
  • • Use hints if you get stuck

Contest Alert

🏆 #CodeEveryDay July 2026

Contest runs July 1 - 31. Complete challenges to climb the leaderboard!

Only the 31 daily challenges shown during this contest count toward points. Earlier dailies don't carry over.

Wally can't hear you

Please sign in to access the AI Assistant

Sign In