- symbols: you can turn any string into a symbol just by putting : in front of it or by using .to_sym or .intern. Once a symbol is created, it never goes away. It does not get garbage collected. It takes allocated memory just once, not every time it is used and is then stored in the symbols table. But use it carefully and think about whether a symbol or a string makes for sense in your context. Remember that using strings is better for memory because the strings do get garbage collected.
- object IDs: every object in Ruby has an ID (check it out with .object_id). A symbol will have the same ID all over your program, strings on the other hand will have a new ID every time they are used in the program
- we then actually wrote some code for RapidFTR and added further success and error handlers to a sortable table
- played a round of Jeopardy with Klaus :D
- In the category "Internet for 300", the answer was "Cookies" - but what's the question? We decided on "What can store information about a user on the browser so that the next time the user visits the page, the server can answer with convenient stuff?" We then also learned, that Rails can create cookies for you, which have a certain shelf life. It's highly insecure to eat them afterwards!
- In the category "Ruby for 500", the answer was "monkey patching". We figured out (..ok, with the help of our host) that monkey patching is when you overwrite something that was already there but wasn't created by you in first place. For example when you fiddle with classes that Ruby defined for you. That's bad! Even if Rails does some monkey patching on Ruby code...humans should not do it!