How to generate sequence of numbers/chars in javascript?

Question

Is there a way to generate sequence of characters or numbers in javascript?

For example, I want to create array that contains eight 1s. I can do it with for loop, bu

Answer 1

Using Jquery:

---

$.map($(Array(8)),function(val, i) { return i; })

This returns:

[0, 1, 2, 3, 4, 5, 6, 7]

---

$.map($(Array(8)),function() { return 1; })

This returns:

[1, 1, 1, 1, 1, 1, 1, 1]

---

Answer 2

If like me you use linspace a lot, you can modify your version of linspace easily like so:

function linSeq(x0, xN) {
    return linspace(x0, xN, Math.abs(xN-x0)+1);
}

function linspace(x0, xN, n){

    dx = (xN - x0)/(n-1);
    var x = [];
    for(var i =0; i < n; ++i){
        x.push(x0 + i*dx);
    }

    return x;
}

You can then use linSeq in any direction, e.g. linSeq(2,4) generates 2,3,4 while linSeq(4,2) generates 4,3,2.

Answer 3

Typescript method based on Ariya Hidayat code:

/**
 * Generates sequence of numbers from zero.
 * @ param {number} count Count of numbers in result array.
 * @ return {Array<number>} Sequence of numbers from zero to (count - 1).
 */
public static sequence(count: number): Array<number>
{
    return Array.apply(0, Array(count)).map((x, i) =>
    {
        return i;
    });
}

Answer 4

The fastest way to define an array of 8 1s is to define it-
var A= [1, 1, 1, 1, 1, 1, 1, 1];

// You'd have to need a lot of 1s to make a dedicated function worthwhile.

// Maybe in the Matrix, when you want a lot of Smiths:

Array.repeat= function(val, len){
    for(var i= len, a= []; i--; ) a[i]= val;
    return a;
}
var A= Array.repeat('Smith',100)

/*  returned value: (String)
Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith, Smith
*/

Answer 5

Without a for loop, here is a solution:

Array.apply(0, Array(8)).map(function() { return 1; })

The explanation follows.

Array(8) produces a sparse array with 8 elements, all undefined. The apply trick will turn it into a dense array. Finally, with map, we replace that undefined the (same) value of 1.

Answer 6

var GetAutoNumber = exports.GetAutoNumber = (L) => {
    let LeftPad = (number, targetLength) => {
        let output = number + '';
        while (output.length < targetLength) {
            output = '0' + output;
        }
        return output;
    }
    let MaxNumberOfGivenLength = "";
    for (let t = 0;t < L;t++) {
        MaxNumberOfGivenLength = MaxNumberOfGivenLength + "9"
    }
    let StartTime = +new Date();
    let Result = [];
    let ReturnNumber;
    for (let i = 1;i <= MaxNumberOfGivenLength;i++) {
        Result.push(LeftPad(i, L))
    }
    for (let k = 0;k != 26;k++) {
        for (let j = 0;j <= 999;j++) {
            Result.push(String.fromCharCode(k + 65) + LeftPad(j, (L - 1)));
        }
    }
    console.log(Result.length)
    return Result;
}
GetAutoNumber(3)

It will generate result like 001-999, A01-A99... Z01-Z99