Programmers tell computers what to do. Learning to program means learning what to tell them. Over the years I've learned many ways to same thing. A second class in programming needs to admit that every career programmer will do the same thing.
Pages here only hint at the breadth of solutions offered to common problems. A competent programmer should know at least one solution, a master, all and then some.
The comparable Hyperglot site offers side-by-side comparisons of popular idioms expressed in various popular languages. website 
History
This site launched in response to interest in my recent #FutureTalk presentation, Song of Code and Content.
This site was founded with 10 pages written elsewhere. That would make it 10% done. There is lots to know.
This is a federated wiki site where I collect the best work from other similar sites. To contribute here you must first launch your own site in the federation.
References
I wrote Federated Wiki while I served as Nike's open-data fellow. I currently work for NewRelic in Portland, Oregon.
Agile programming and Wiki hypertext emerged together out of a single vision of completing each other's work. Twenty years later we see opportunity to direct this collaboration toward more difficult problems. This is not your father's wiki.