Node.js outlet arrays of arrays?
Hi
I'm new to node.js and not sure to understand what would
be the best way to recover a list of lists (or array of arrays) from node.script.
In Max I use most of the time the bach library to deal with lists of lists (lllls) and inside javascript this is obviously not a problem either.
But to make the contact between them doesn't seem so easy : of course I'm able to feed an array with lists from Max to node.script by iterating, but I don't really know how to do this from node.script to Max.
For now, when I just feed a nested array to MaxAPI.outlet, so node.script should return :
[ [ "a", "b" ], [ "a", "b", "d" ], [ "a", "l", "k", "j" ], [ "a", "l", "k" ], [ "a", "l" ], [ "a", "b", "d", "f" ], [ "a", "l", "k", "i" ], [ "a", "b", "d", "f", "g" ], [ "a", "b", "d", "e" ] ]
Outside, Max interprets the data as a list of distinct dictionaries :
dictionary u153005768 dictionary u930005769 dictionary u599005770 dictionary u806005771 dictionary u849005772 dictionary u746005773 dictionary u320005774 dictionary u936005775 dictionary u839005776
and I'm not really sure how to deal with those...
Thanks in advance for your help !
Julien
Have a look at the Squiggle example for some ways to parse dictionaries of dictionaries. I would recommend packing your structured array into a JSON object (in nodeJS) before passing it out so it comes out as a single dictionary message. So it would look something like:let myOutput = {
"data": myArray
};
maxApi.outlet(myOutput);
Thanks Andrew
I managed to feed the result of node.script as a single dictionary message to a dict object, by following your example.
Now the dict contains :
{
"data" : [ [ "a", "b" ], [ "a", "b", "d" ], [ "a", "b", "d", "f" ], [ "a", "b", "d", "f", "g" ], [ "a", "l", "k", "i" ], [ "a", "l" ], [ "a", "b", "d", "e" ], [ "a", "l", "k" ], [ "a", "l", "k", "h" ], [ "a", "l", "k", "j" ], [ "a", "b", "c" ] ]
}
Unfortunately, I can't find a way to extract the elements.
getsize data returns indeed "data 11" from the second outlet
but get data[4] returns "data[4] <atomarray-object>" and I don't know what to do with this
I tried to solve this by using dict.unpack and dict.iter as shown in Squiggle,
but the atomarray-object always causes a problem eventually... :(
you can use JS to transform your Dict into a JS object, and then access the data as a JS object. The trick is to use JSON.parse with the output of Dict.stringify():
var jsob = JSON.parse(d.stringify());
Yep, Rob makes a great point here, and cool trick. It's easy to forget (especially for me!) that JS is really great for unravelling this data, and trying to do it all in-patcher can get pretty wacky.
thanks Rob, actually this didn't work for me because I'm trying to stay outside of js as much as possible (I'm more of a Lisper, among other reasons :) so going back and forth between node, Max and js isn't great for me
but your example made me realize I could just iterate through the array of arrays inside node.script
and MaxAPI.outlet each array one after the other
finally I packed them all back together with bach.collect
Hello just wanted to chime in as I am having a similar problem extracting data from a dictionary with arrays inside arrays. I am using JS and am able to get the data out but it is also returning just multiple <atomarray-object> messages for all the pieces of data and I need to output the individual numbers from the data. I tried to access the data as a JS object but it is not working with JSON.parse and Dict.Stringify()!
Here is the patch with the JS code in a comment, I am so confused and am trying to learn Javascript. Can anyone help me get the individual data pieces from the dictionary?
thanks!
Just another plug for doing the outer array iteration within JS world, but also consider that you can help the rest of the patch with additional start/end messages.
For example, if I use JS to generate a chord progression, I might have an outer array that represents the chord progression and each chord is a variable length inner array of MIDI note numbers.
In this scenario, I will use the "done" message design pattern, but it requires different patching on the receiving end. Basically I loop over each chord separately and send each out as an individual list and then send a "done" message out the [js] (or [node.script]) object's outlet when the JS loop is done. The plain [js] object version would look something like:
for (var i = 0; i < chordProgression.length; i++) {
outlet(0, chordProgression[i]);
}
outlet(0, "done");
Going from the [js] object into a [route done] object means I have a bang that happens once the entire outer array loop is finished.
Then I just process the inner arrays individually, for example, throwing them into a [coll] for sequencing. But using either a "start" and/or "done" message before/after is enough to help the rest of a patch make decisions. I realized that the purpose of the outer array (chord progression) was just to wrap up a unit of work and that an explicit message can serve the same purpose.