Data objects

[shiffman]

@benfry and I were just talking about the data classes from Processing like IntDict, FloatDict, StringList etc in JS and we came to a conclusion that it would be nice to implement some of these for p5. I am thinking:

• NumberList
• StringList
• NumberDict
• StringDict

Obviously without types in JavaScript there can just be a Dict and List, however, I think it would be nice to separate out Numbers and Strings. For example, there are enough API differences and reference-wise it would be confusing for it to be all in one. If you want a more advanced list or dictionary with multiple data types in JS then you would implement it yourself with native JS arrays and/or objects. But these would be simple ways to do quick operations on lists and dictionaries with basic data types. This aligns with Processing: IntDict for simple dictionary, HashMap from Java for more advanced.

@therewasaguy am I correct that these have not been started yet? I am very happy to take on working on these (likely after the ITP semester) and thought it might be nice to start the discussion here.

Thoughts?

[GoToLoop]

I'm all in favor. But please, make it high performance. For example, the internal array shouldn't be resized all the time, but pre-allocated to some reasonable size like Java does for an ArrayList! :D

[GoToLoop]

Perhaps it'd be better if NumberList be split into IntList & FloatList, just like Processing 2.

IntList would be based on Int32Array:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array

And FloatList on Float32Array:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array

I'd also be interested in faster ArrayList & ArrayDeque data structures for p5.js! 😸
At least Map, WeakMap, Set & WeakSet already exist in JS: 😹

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakSet

[therewasaguy]

@shiffman sounds great! I haven't worked on these, only on the Table class and Table Row. Maybe there will be insights from this that can be applied to Table, too. I like the idea of IntList and FloatList using typed arrays the way @GoToLoop suggests.

[benfry]

Typed arrays are likely to be slower, definitely check before getting too far into that. They're built for moving a lot of fixed binary data around, not for quick random read/write of list elements, the way that Int/FloatList work.

[shiffman]

I completed a first pass over NumberList in https://github.com/shiffman/p5.js/tree/dataobjects. It's not entirely clear to me whether this is entirely needed given how much functionality there is in a native JS array, but it's a good learning process for me.

@lmccart, do you think I should implement all four objects (NumberList, StringList, NumberDict, StringDict) before submitting a pull request or might it be worth bringing NumberList in with an example or two as a trial run?

Also as a follow-up to previous discussion I don't see tremendous value in separating out ints from floats at the moment, but feel free to let me know if you disagree.

[shiffman]

We are teaching the topic of "data" at ITP next week. One of the examples I typically demonstrate is simple "word counting." Processing has IntDict which makes this sort of task easy. JS objects can be used as dictionaries with the key being the word and the value being the count. I have examples of this for my A to Z class.

Should I implement a NumberDict (better name?) for p5.js or shall I just make an example that uses a JS object? @lmccart

[lmccart]

I think this makes sense. The four you list in the first post seem reasonable to me, not that you need to implement them all right now. :) If you'd like to take a pass at NumberDict, that'd be fantastic.

[shiffman]

Awesome, I'll work on implementing NumberDict for this week's ICM and port my Learning Processing examples. Part of me is wondering if we should just have a single Dictionary object and let the typing be flexible. But let's start this way for now and see how it goes.