Data Structures and Algorithms

I mentioned it in the first comment:

the reason I tend to recommend B-Tree maps over hash maps for ordinary programming is consistent iteration order. It is simply too easy to run into a situation where you think iteration order doesn’t matter, but then it turns out it does in some subtle unforeseen way.

I’m not talking about bugs in the implementation of the map itself, I’m talking about unforeseen consequences in the user’s code since they may not anticipate properly for the randomness in iteration.