I'm trying to make an array of empty arrays, the amount of which depends on N. Currently, I have this:
var seqList = [];
for(var i = 0; i < N; i++) {
seqList.push([]);
}
Is this the most efficient way of doing it? Or might there be another way?
Your method is the most efficient one. You can also use Array.fill method from ES6 but it is not the most efficient.
let n=10;
let array=Array.from({ length: n }, () => []);
console.log(array);When you are using let array=[] you're telling the interpreter to create a new runtime array.
If you use:var a = new Array() you're telling the interpreterthat you want to call the constructor Array , generate an object and creating your array.
Array#fill is the cleanest
let count = 10;
let seqList = Array(count).fill([]);
Update:
After being schooled by @deceze I would rather use since the example above fails is a horribly subtle way.
let count = 10;
let seqList = Array(count).fill(0).map(_ => []);
Is it better than your attempt? Probably not. I've just become so used to reading map/reduce, I prefer it. YMMV
seqList[0].push('foo')… try it.
push?. Per the question the size "depends on N"console.log(seqList). Then you'll see the problem with this approach.map from it. Thanks for the heads-up