Creating multiple arrays of objects

Question

For an experiment I'm writing, I have to make six of the kind of list below.

var list1 = [];
var enc_len_1 = pregenerated_faces[1].encoding_faces.length;
var rec_len_1 = pregenerated_faces[1].recall_faces.length; 

for (var i = 0; i < enc_len_1; i++){
    var obj_encode = { 
        'encode': pregenerated_faces[1].encoding_faces[i]
    };
    list1.push(obj_encode);
};

for (var i = 0; i < rec_len_1; i++){
  var obj_recall = { 
      'reacall': pregenerated_faces[1].recall_faces[i]
  };
  list1.push(obj_recall);
};

Each list will look like this: list = [{encode: ...jpg}, {encode: ...jpg}..., {recall: ...jpg}, {recall:...jpg}...]

What is a smarter way to make six of these without writing six-fold redundant code? Oh, also, pregenerated_faces is an array of .json objects containing all the encoding and recall faces image strings.

Can you provide a code block of how you want that function to actually work? Like a dummy function that will work for you? — tarun jain
– tarun jain, Commented Jun 19, 2020 at 8:11
It isn't a function, but a list variable that I'll use as a timeline variable in JsPsych. in the code below, i'll iterate over the list created above. ` var trial1 = { timeline: [generateListStart, displayList, distractor, recognitionTest], timeline_variables: list1 } ` — JadeHippo
– JadeHippo, Commented Jun 19, 2020 at 8:16
Yes, you want to create 6 variable lists without writing the whole code again... I am actually thinking of separating the create list code to a function, so you can have N list with the given definition. — tarun jain
– tarun jain, Commented Jun 19, 2020 at 8:24
That is a good idea, but I think that might be difficult given that the number of lists is "fixed" in that I create the json array via python; this script is where I decide how many lists to create, in this case, six. But once I set it, the number of lists cannot be changed.. or can it? Maybe the information about how many lists are created can be translated from python to javascript by creating a field in the json file. — JadeHippo
– JadeHippo, Commented Jun 19, 2020 at 8:36
I hope that you have to iterate over pregenerated_faces and not encoding_faces — tarun jain
– tarun jain, Commented Jun 19, 2020 at 8:42

Julien Maret · Accepted Answer · 2020-06-19 08:52:15Z

1

var lists = [];
for (var face of pregenerated_faces) { //should loop 6 time
  var list = [];
  face .encoding_faces.forEach( e => list.push({'encode': e}));
  face .recall_faces.forEach( e => list.push({'recall': e}));
  list.push(list);
}

edited Jun 19, 2020 at 8:52

answered Jun 19, 2020 at 8:46

Julien Maret

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Comments

tarun jain · Accepted Answer · 2020-06-19 08:40:52Z

0

Check this, I have created a function that will give you N lists depending upon the input size of your pregenerated_faces, and your list renderer is also out of the implementation so that it can be used anywhere... and can be changed too

function getNObjects(N, keyCallback) {
  const output = []
  for (var i = 0; i < N; i++) {
    output.push(keyCallback(i));
  }
  return output
}

// your code
function createList(index) {
  var list = [];
  var enc_len = pregenerated_faces[index].encoding_faces.length;
  var rec_len = pregenerated_faces[index].recall_faces.length;

  for (var i = 0; i < enc_len; i++) {
    var obj_encode = {
      'encode': pregenerated_faces[index].encoding_faces[i]
    };
    list.push(obj_encode);
  };

  for (var i = 0; i < rec_len; i++) {
    var obj_recall = {
      'reacall': pregenerated_faces[index].recall_faces[i]
    };
    list.push(obj_recall);
  };
  return list
}
// Test case
const pregenerated_faces = [{
    name: "Ardis Pool",
    gender: "male"
  },
  {
    name: "Barbra Panganiban",
    gender: "female"
  },
  {
    name: "Ralph Sales",
    gender: "male"
  },
]
// Test Function
function testFunction(index) {
  var list = [];
  var enc_len = pregenerated_faces[index].name
  var rec_len = pregenerated_faces[index].gender

  var obj_encode = {
    'encode': enc_len
  };
  list.push(obj_encode);
  obj_recall = {
    'reacall': rec_len
  };
  list.push(obj_recall);
  return list
}

const [one, two, three] = getNObjects(3, testFunction);
console.log(one, two, three)

answered Jun 19, 2020 at 8:40

tarun jain

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2 Comments

JadeHippo Over a year ago

Thanks, but could you clarify what the code is doing below the "test case" comment?

tarun jain Over a year ago

The test case is just to show how the function will work... pregenerated_faces is a list from which we have to create multiple lists for each index... testFunction is the list renderer... which will create the list for that index... and I am using es6 syntax to spread the output from getNObjects to have all the list at once.

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