Alex questions

• Rails/Haml: adding a parentclass every n iteration
• Rails / Postgres: “must appear in the GROUP BY clause or be used in an aggregate function”
• Intersection of two arrays with repetition
• AngularJS : Update A Function In RealTime
• AngularJS : filter and bold part of the result
• Java: difference between A x = new A() and A x = new B() when B extends A [duplicate]
• Rails: comparison of Status with Status failed
• Pdf.js: rendering a pdf file using a base64 file source instead of url

Alex answers