Why console.log(largest) is giving the result 9 instead of 15 , like why it iterated only till index 3 in the for loop

Question

let userInput = [6, '1 6 7 9 10 15'];

let arr = userInput[1].split(" ");

let largest = arr[0];

console.log(arr);
for (let i = 1; i < arr.length; i++) {
  if (arr[i] > largest) {
    largest = arr[i];
  }
}
console.log(largest);

I wanted the largest number to be displayed as 15 but it's showing 9 . Idk why it iterated only till index 3 .

(https://i.stack.imgur.com/hfVZd.jpg)

Because the string '9' comes after the string '15' alphabetically. You probably want to convert your array into numbers while you split it. — Welbog, Feb 21 '23 at 21:32
When you split the string you end up with an array of *strings*, not numbers. — Pointy, Feb 21 '23 at 21:33
You made string array, so, 9 is greater than 15 by alphabetical order. — tzztson, Feb 21 '23 at 21:34
Convert each element to a number: `let arr = userInput[1].split(" ").map(Number);` — Unmitigated, Feb 21 '23 at 21:36
https://stackoverflow.com/questions/4291447/convert-string-into-array-of-integers — epascarello, Feb 21 '23 at 21:52

score 1 · Answer 1 · answered Feb 21 '23 at 21:37

The reason is numbers in arr array are string and you should parse it in to the Int !

like this :

let userInput = [6, "1 6 7 9 10 15"];

let arr = userInput[1].split(" ");

let largest = parseInt(arr[0]);

console.log(arr);
for (let i = 1; i < arr.length; i++) {
  if (parseInt(arr[i]) > parseInt(largest)) {
    largest = arr[i];
  }
}
console.log(largest);

score 1 · Accepted Answer · answered Feb 21 '23 at 22:04

Because you are splitting a string and split(ed) string will result in an array of strings. So basically in your for loop, you are comparing strings instead of integers.

console.log("Welcome to Programiz!");
let userInput = [6, "1 6 7 9 10 15"];

let arr = userInput[1].split(" ").map(Number);

let largest = arr[0];

console.log(arr);
for (let i = 1; i < arr.length; i++) {
  if (arr[i] > largest) {
    largest = arr[i];
  }
}
console.log(largest);

you should be careful here because if the string you are splitting has some elements that can't be converted to Number, it will convert the string to NaN and it might cause bugs in your program.

tzztson · Answer 3 · 2023-02-21T21:48:33.260

0

let userInput = [6, '1 6 7 9 10 15'];

let arr = userInput[1].split(" ");

let res = arr.map(e=>parseInt(e))

console.log(Math.max(...res))

If you want max value, it should be answer.

edited Feb 21 '23 at 21:48

answered Feb 21 '23 at 21:42

tzztson

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Why console.log(largest) is giving the result 9 instead of 15 , like why it iterated only till index 3 in the for loop

3 Answers3