๐Ÿค‘ Join the Treehouse affiliate program and earn 25% recurring commission!

New No-Code Track! ๐Ÿš€ New videos dropping every weekโ€”start learning today!

๐ŸŒŸ Dreaming of a bright future? ๐ŸŽ“ Ask about the Treehouse Scholarship program! ๐Ÿš€

โœจ Earn college credits in Cybersecurity, JS, HTML, CSS and Python

  • Treehouse Logo
  • Plans
    Chevron
    • For Individuals
    • For Businesses
    • For Schools
    • For Libraries
    • For Military
  • Library
    Chevron
    • All Courses
    • Tracks
    • College Credit
  • Techdegree
    Chevron
    • Overview
    • Front End Development
    • Full Stack JavaScript
    • Data Analysis
    • UX Design
    • Python
  • Community
    Chevron
    • Community Projects
    • Live Sessions
    • Code Adventures
    • Discord
    • Forum
    • Success Stories
    • Treehouse Links
    • 100 Days of Code
  • Resources
    Chevron
    • Career Toolbox
    • CodeForward
    • Free Treehouse Near Me
    • Jobs
    • Blog
    • Support
    • About
  • For Individuals For Businesses For Schools For Libraries For Military
  • All Courses Tracks College Credit
  • Overview Front End Web Development Full Stack JavaScript Python Development Data Analysis UX Design
  • Community Projects Live Sessions Code Adventures Discord Forum Success Stories Treehouse Links 100 Days of Code
  • Career Toolbox CodeForward Free Treehouse Near Me Jobs Blog Support About
  • Sign In
  • Free Trial
Instagram Twitter Facebook YouTube LinkedIn
    • Newest
      • Newest
      • Active
      • Unanswered
      • Featured
    • All Topics
      • All Topics
      • • General Discussion
      • • AI
      • • Android
      • • APIs
      • • Coding for Kids
      • • College Credit
      • • Computer Science
      • • CSS
      • • Data Analysis
      • • Databases
      • • Design
      • • Development Tools
      • • Digital Literacy
      • • Game Development
      • • Go Language
      • • HTML
      • • Java
      • • JavaScript
      • • Learning Resources
      • • Machine Learning
      • • No-Code
      • • PHP
      • • Professional Growth
      • • Python
      • • Quality Assurance
      • • React
      • • Ruby
      • • Security
      • • Swift
  • David Klaphaak
    David Klaphaak
    12,924 Points

    Why won't this validate method work in code challenge?

    Posted March 20, 2016 2:03am by David Klaphaak
    David Klaphaak
    12,924 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    0 Answers

  • MUZ140122 Emmanuel Kavhuru
    MUZ140122 Emmanuel Kavhuru
    5,605 Points

    Can't get this code work on challenge 2

    Posted May 8, 2015 8:26am by MUZ140122 Emmanuel Kavhuru
    MUZ140122 Emmanuel Kavhuru
    5,605 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    2 Answers

  • John Martens
    John Martens
    8,689 Points

    Customer rails validator not working

    Posted April 28, 2015 10:15am by John Martens
    John Martens
    8,689 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    1 Answer

  • Shawn Wilson
    seal-mask
    .a{fill-rule:evenodd;}techdegree
    Shawn Wilson
    iOS Development Techdegree Student 7,049 Points

    Build a custom validator that ensures that no Contactโ€™s last_name is Evil. issue with challenge

    Posted April 6, 2015 8:10pm by Shawn Wilson
    .a{fill-rule:evenodd;}techdegree
    Shawn Wilson
    iOS Development Techdegree Student 7,049 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    2 Answers

  • Erik Van de Water
    PLUS
    Erik Van de Water
    Courses Plus Student 299 Points

    Correct answer for custom validator?

    Posted March 3, 2015 6:12pm by Erik Van de Water
    Erik Van de Water
    Courses Plus Student 299 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    2 Answers

  • gbp
    gbp
    5,619 Points

    ActiveRecord code challenge: Build a custom validator that ensures that no Contactโ€™s last_name is Evil.

    Posted February 19, 2015 5:37am by gbp
    gbp
    5,619 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    2 Answers

  • Gavin Ralston
    Gavin Ralston
    28,770 Points

    Having trouble with custom validation

    Posted December 2, 2014 11:32pm by Gavin Ralston
    Gavin Ralston
    28,770 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    1 Answer

  • Michael Williams
    Michael Williams
    8,074 Points

    Validation MVC ActiveRecord

    Posted July 11, 2014 7:24pm by Michael Williams
    Michael Williams
    8,074 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    2 Answers

  • Michael Mykytyn
    Michael Mykytyn
    23,440 Points

    2nd Validation Quiz

    Posted May 30, 2014 4:48pm by Michael Mykytyn
    Michael Mykytyn
    23,440 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    4 Answers

  • Sebastian Bachmann
    Sebastian Bachmann
    7,046 Points

    [Done - Solution included] Build a custom validator that ensures that no Contactโ€™s last_name is Evil.

    Posted May 28, 2014 5:16am by Sebastian Bachmann
    Sebastian Bachmann
    7,046 Points
    • Ruby
    • ActiveRecord Basics
    • Validation
    • Errors 2

    3 Answers

Posting to the forum is only allowed for members with active accounts.
Please sign in or sign up to post.

    Treehouse

  • About
  • Blog
  • Careers
  • Community
  • Stories
  • Shop
  • Contact
  • Gift Card

See Full Catalogue

Techdegree

  • Front End Web Development
  • Full Stack JavaScript
  • Python Development
  • Data Analysis
  • UX Design

Tracks

  • Learn to Code for Beginners
  • Beginning Python
  • Beginning SQL
  • Beginning Java
  • ...see more

Courses

  • JavaScript Basics
  • Intro to HTML & CSS
  • Python Basics
  • CSS Layout
  • ...see more

Explore

  • Plans
  • Affiliates
  • Perks
  • Free Treehouse Near Me
  • Treehouse for Libraries
  • Treehouse for Businesses
  • Twitter
  • YouTube
  • Facebook
  • LinkedIn
  • Instagram
Terms & Conditions | Privacy

© 2025 Treehouse Island, Inc.