I have an array [1, 5, 20, 17, 6, 12, 13, 20, 1, 14, 20].

Whenever the element of the array is equal to 20 I would like to wrap it with an asterisk on either side like this [1, 5, *20*, 17, 6, 12, 13, *20*, 1 , 14, *20*].

How can I achieve this?

I have an array [1, 5, 20, 17, 6, 12, 13, 20, 1, 14, 20].

Whenever the element of the array is equal to 20 I would like to wrap it with an asterisk on either side like this [1, 5, *20*, 17, 6, 12, 13, *20*, 1 , 14, *20*].

How can I achieve this?

• javascript
• arrays

3 Answers 3

You can use map

let arr = [1, 5, 20, 17, 6, 12, 13, 20, 1, 14, 20]

let result = arr.map(o => o === 20 ? '*20*' : o);

console.log(result);

Doc: map()

You can use Arrays forEach to modify the elements of the array. elem is each element and i is the respective index. We are using forEach to modify the existing array. Since this is what you desired..

let arr = [1, 5, 20, 17, 6, 12, 13, 20, 1, 14, 20]

arr.forEach((elem, i) => {
  if (elem === 20) {
    arr[i] = "*20*"
  }
})

console.log(arr)



function rollDice(max, times, bonus) {
        var rolls = [1, 5, 20, 17, 6, 12, 13, 20, 1, 14, 20];
        rolls.forEach((elem, i) => { if (elem === 20) { rolls[i] = "twenty" } });
        for (var i = 0; times > i; i++)
        { 
            max = Math.floor(max);
            rolls.push(Math.floor(Math.random() * max) + 1 | + parseInt(bonus));
        }
        console.log(rolls);
} 
    
rollDice(20, 5);

The problem you are experiencing is that you need to convert the integer number into strings. JavaScript has several ways to cleverly do this behind-the-scenes, but if you are still gaining an understanding of that, it's better to be explicit about what data types you start with (integers), and what data types you expect to end with (strings).

You transform the array, "mapping" over each item, transforming it to a string, and then if the string matches "20", you add the asterisks.

const start_array = [1, 5, 20, 17, 6, 12, 13, 20, 1, 14, 20];

const new_array = start_array.map((integer) => {
  let number_string = integer.toString();
  if (number_string === "20") {
    number_string = "*" + number_string + "*";
  }
  return number_string;
})

console.log(new_array);