Replacing values in Javascript array at precise location

Question

I have two JavaScript array.

var arrOne = ["1.", "2.", "3.", "4.", "5."];
var arrTwo = ["3.4", "1.1", "2.3", "1.5", "10", "2.4" , "44"];

For every item in first array (arrOne), I want to check how many items from second array (arrTwo) contains values starting with the value from first array.

Ex: I will check how many items in arrTwo starts with value "1.". It should return me "1.1", 1.5.

After I find these values I want to replace 1 with 1.1 & 1.5 in the first array.

So the final output should look like: ["1.1", "1.5", "2.3", "2.4", "3.4", "4.", "5."];

I know how to find the values but not sure to replace the values .

Answer 1

You can use two loops, checking the index of the arrOne element within arrTwo. If a match exists, add it to the final array of values. Something like this:

var arr = [];
$.each(arrOne, function (i, val) {
    var valFound = false;
    $.each(arrTwo, function (i, v) {
        if (v.indexOf(val) == 0) {
            valFound = true;
            arr.push(v);
        }
    });
    !valFound && arr.push(val);
});

Example fiddle

Alternatively in native JS only:

var arr = [];
for (var i = 0; i < arrOne.length; i++) {
    var valFound = false;
    for (var n = 0; n < arrTwo.length; n++) {
        if (arrTwo[n].indexOf(arrOne[i]) == 0) {
            valFound = true;
            arr.push(arrTwo[n]);
        }
    };
    !valFound && arr.push(arrOne[i]);
};

Example fiddle

Answer 2

You can try this:

var arrOne = ["1.", "2.", "3.", "4.", "5."];
var arrTwo = ["3.4", "1.1", "2.3", "1.5", "10", "2.4" , "44"];

var arrResult = [];

for (var i = arrOne.length - 1; i >= 0; i--) {
    for (var x = arrTwo.length - 1; x >= 0; x--) {
        if(arrOne[i] == arrTwo[x].substring(0,arrOne[i].length)) {
            arrResult.push(arrTwo[x])
        }
    };
};

console.log(arrResult);