Cloth or Die

You’ve probably heard of Adam Savage, of Mythbusters and tested.com fame. Lots of fun stuff there. And lots to learn as well. Every once and a while he’ll need to cut something. Depending on what it is, he’ll reach for a different tool. Plasma cutter for steel plate, Pipe cutter for pipe. Scissors for paper, cloth, aluminum and sheet metal. 

Unsurprisingly, he doesn’t use the same scissors for all of them. Aluminum and sheet metal use one set, and they’re a lot beefier and have a much longer moment arm. One thing that might be surprising is that he doesn’t use the same scissors for cloth and paper. In fact, there are lots of kinds of scissors. Sure, they’re all hand operated and have moving blades, but they’re pretty different and some have specific uses. And apparently one of the mst damaging things you can do with a pair of scissors is cut paper. As he put it in his 20 minute video on scissors, on his cloth scissors he wrote “cloth or die” to make sure no one gets it wrong.

The same holds true in software. Consider the Collection. There are lots of different collection types, but in general a collection is a bag of stuff. It Depends. With enough extra code you can use almost any collection type to provide almost any functionality. But that doesn’t mean you should. What kind of collection you should use depends on what you want/need to do with the collection. Need really fast access to a statically indexed/ordered collection? Probably want an array. Or maybe a hash/map. Need to guarantee that there’s only one value for a given key? Try a set. Are there more reads or writes? Does it need to be sorted somehow? Do you need to maintain the order things were added? Are there memory constraints? All these things go into the decision making process.

So next time you need to maintain a collection of things make sure you know how you’re going to use it. And make sure you don’t earn the Wrong Scissors (de)merit badge.