如何刷新数组的内容？

Question

I have an array which is taking values over the space of a second and calculating the average. The array is then permanently storing the values. I need them to remove the values after the average has been calculated. I have tried clearing the array at the end of the calculateAverage function using levelMeasurements = []; and levelMeasurements = 0; but that does not work.

Any help on this would be greatly appreciated, thanks!

My code:

var levelMeasurements = [];

function collectLevelMeasurements() {
    levelMeasurements.push(averagingLevel);
}
var collectInterval = window.setInterval(collectLevelMeasurements, 0);

function calculateAverage() {
    window.clearInterval(collectInterval);

    var avg = 0;

    for (counter = 0; counter < levelMeasurements.length; counter++) {
        avg += levelMeasurements[counter] / levelMeasurements.length;
    }

    averageAbsoluteLevel = Math.abs(avg);
    averageDbLevel = Tone.gainToDb(averageAbsoluteLevel) * scale + offset;

    console.log("Measure for 5 minutes: average level is:" + averageDbLevel);

}
window.setInterval(calculateAverage, 1000);

Answer 1

You can try following:

levelMeasurements.length = 0.

Or refer more solution at here: How do I empty an array in JavaScript?

Answer 2

Your collectInterval timeout is never reinstated after the first time calculateAverage is called, unless the issue is something else not visible from the code.

In your code calculateAverage is called every 1000 milliseconds, but the values stored in levelMeasurements are not updated after the first window.clearInterval .

I made a simplified snippet without Tone lib:

 var levelMeasurements = []; //added this as a easy source of values let count = 0; function collectLevelMeasurements() { // levelMeasurements.push(averagingLevel); levelMeasurements.push(count++); } var collectInterval = window.setInterval(collectLevelMeasurements, 0); function calculateAverage() { window.clearInterval(collectInterval); var avg = 0; for (counter = 0; counter < levelMeasurements.length; counter++) { avg += levelMeasurements[counter] / levelMeasurements.length; } averageAbsoluteLevel = Math.abs(avg); averageDbLevel = averageAbsoluteLevel; //prolly dont need tone lib for this example // averageDbLevel = Tone.gainToDb(averageAbsoluteLevel) * scale + offset; console.log("Measure for 5 minutes: average level is:" + averageDbLevel); //reset these variables levelMeasurements = []; count = 0; console.log(levelMeasurements)//empty array at this point //reset the collectInterval! collectInterval = window.setInterval(collectLevelMeasurements, 0); } window.setInterval(calculateAverage, 1000);