Loop to create array + loop increment?

Question

I wanted to create a function which gets called upon-page load and generates a graph based on what user inputs (multiple datasets, using chart.js).

Decided to rely on prompt() for initial testing, but soon ran into a problem.

function defineDatasets(itt){
 for(i=0; i<itt; i++){
 var dataSet+i=[]; // <--- Does not result in a array called "dataSet0[], ..." etc
 }
}

So my question is, if and how could this be achieved?

Answer 1

If you're trying to suffix your arrays with an index, why not just make an array of arrays? Also be sure to define your dataSet outside the function scope:

let dataSet = [];
function defineDatasets(itt) {
 for(var i = 0; i < itt; i++) {
 dataSet.push([]);
 }
}
console.log(dataSet[0]); // []

Now instead of referencing these arrays with dataSetN, you can do dataSet[N], where N is the Nth dataSet index.

• Patrick Roberts: It might be beneficial to dataSet = []; before the for loop so that multiple calls to defineDatasets() does not append more empty arrays to dataSet if it's already been initialized.
• Bucket: @PatrickRoberts - True. Alternatively, changing dataSet.push([]) to dataSet[i] = [] would mitigate this issue.
• Patrick Roberts: That'd actually be even worse. Consider defineDatasets(20); /* do stuff with dataSet... */ defineDatasets(10); /* expect dataSet.length === 10, but it's actually still 20 */