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javascriptarraysstringmultiplication
TorontoJ10
TorontoJ10

Reputation: 23

Producing Strings from Array Multiplication

I am looking to create a javascript function that outputs strings as a result of array multiplication.

The first number of the array will be multiplied by the second, resulting in a string as below.

For ex. when:

console.log(repeatNumbers([[1, 10]]));
console.log(repeatNumbers([[1, 2], [2, 3]]));

The result would be:

1111111111
11, 222

I am struggling getting past returning simple multiplication out puts such as 1*10 = 10, and producing a full string (w/o commas) instead.

Any advice would be great - thanks.

Upvotes: 0

Views: 44

Answers (2)

Prince Hernandez
Prince Hernandez

Reputation: 3731

actually you can do it using a map over the array and then apply the repeat function of string (you have to parse from number to string).

repeatNumbers = (array) => array.map(item => item[0].toString().repeat(item[1]));

console.log(repeatNumbers([
  [1, 10]
]));

console.log(repeatNumbers([
  [1, 2],
  [2, 3]
]));

Upvotes: 3

CRice
CRice

Reputation: 32176

You can use the array constructor function to create an array of a given length. Then use the .fill array method to fill the new array with the right thing. Finally, you can use join to convert the filled array back to a string. In your case, for each pair, the first element is what to fill the array with, and the second is the desired length.

Perform that process for each item in the passed array (using map), and join them with commas, and you get the result from your example:

function repeatNumbers(arr) {
  return arr
    .map(pair => Array(pair[1]).fill(String(pair[0])).join(""))
    .join(", ");
}

console.log(repeatNumbers([[1, 10]]));
console.log(repeatNumbers([[1, 2], [2, 3]]));

Upvotes: 1

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