I'm using sparse arrays to be memory efficient with huge datasets. (and to signal the difference between a hole and a undefined or null entry) adding holes at the end is fine by setting datapoints.lentgh.
datapoints = [10,,,20,,,10,1]
No I face the problem how to insert a hole (say before 20)
datapoint.splice(3,0)
does not work, and I can't find a (easy) method to insert holes. (Think I have to rebuild the array but thought to ask before)
Or is there a way to change a "defined" entry into a hole? delete datapoint[4]; creates an undefined entry not a hole :(
Your sparse array is actually an object. You can delete items and you can add items.
Let's suppose you want to add k holes before position offset. Then:
datapoints = [10,,,20,,,10,1];
function addHoles(offset, k, datapoints) {
let migration = {};
for (let key in datapoints) {
let intKey = parseInt(key);
if (intKey >= offset) {
migration[intKey] = datapoints[intKey];
delete datapoints[intKey];
}
}
for (let key in migration) {
let intKey = parseInt(key);
datapoints[intKey + k] = migration[intKey];
}
return datapoints;
}
console.log(addHoles(3, 3, datapoints));Think I could work with
datapoint.splice(3,0,undefined);
delete datapoint[3]
It looks like that I have a hole now ....