Error when using data tables

[jdonwells]

getColumn: one common error and one subtle error explained

The most common error with getColumn by far seems to be wrapping it in [ ]s. You end up with an array (returned by getColumn) inside an array (created by [ ]) and that doesn’t do what you want at all. So just write var cats = getColumn("Cats","Name");. No ( )s and no [ ]s. I wrote a more complete explanation here Everything You Wanted to Know About App Lab Arrays, But Were Afraid to Ask. The subtle error that can result is a race condition. A race condition happens when you have two or more s…

Everything You Wanted to Know About App Lab Arrays, But Were Afraid to Ask

Everything You Wanted to Know About Arrays, But Were Afraid to Ask. [ ] have two uses. One is to create an array and potentially initialize it. So for example: var a = [1,2,3]; That creates an array and assigns it to a variable. Is that variable an array now? No, it is not. Trick question. Variables don’t have types in Javascript. a is a variable that has an array value. It could just as easily hold a number or a string. Variables don’t care. I see a lot of var cats = [getColumn("Cats","Nam…