I have group of numbers. Without using methods, how to pick the index of the smallest number in JavaScript? Explain, how the code will work.
let numbers = [20, 90, 10, 324, 9, 73] //Example array of numbers.
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2Smallest index of the smallest number? You mean smallest number index? Please provide example input/output and what you already tried.ulou– ulou2021-04-27 21:29:32 +00:00Commented Apr 27, 2021 at 21:29
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1Welcome to Stack Overflow! This is not a website where people write code for you so that you don't have to. If you need help debugging code that you have written, you must post a Minimal, Complete, and Reproducible example and explain the specific problem with your code.Hamms– Hamms2021-04-27 21:36:12 +00:00Commented Apr 27, 2021 at 21:36
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2 Answers
Barebones, without methods:
let numbers = [20, 90, 10, 324, 9, 73]
let smallest = 0
for (i in numbers) {
if (numbers[smallest] > numbers[i]) smallest = i
}
console.log(smallest)First, we make a variable "smallest" and set it to 0, which is the first index of the array. Then, we go through the entire array and see if there's a number smaller than numbers[smallest], the initial value of which is 0. If there is, each time smallest is set to the index of that smaller number.
By the end of the array, we have the variable smallest set to the index of the smallest number in the array. That's the solution without methods.
Using array methods and the Math library:
let numbers = [20, 90, 10, 324, 9, 73]
let smallest = numbers.indexOf(Math.min(...numbers))
console.log(smallest)Math.min()takes a list of numbers and returns the smallest....numbersis what's called "spreading".Math.min()takes parameters, not an array, (Math.min(1, 2, 3)notMath.min([1, 2, 3]). So...numbersturns[20, 90, 10, 324, 9, 73]into(20, 90, 10, 324, 9, 73)- The
.indexOf()method takes a value and finds the index of that value in an array.
5 Comments
Phil
Instead of setting smallest = 0, just set smallest = numbers[0] and replace it if a lesser value if encountered. This will eliminate the negative numbers problem.
almarc
Can't see why it'd produce wrong results with negative numbers. Can you provide an example? My tests with negative numbers provided correct results.
abdulazeez
Thanks for the feedback! I really appreciate that
almarc
No problem! If a post answers what you were looking for, don't forget to accept it as a correct answer :)
susilogn
how if there are multiple minimum value in set of array. can we get the multiple index ?
You can get the smallest number first
let numbers = [20, 90, 10, 324, 9, 73];
let smallest = Math.min(...numbers);
Then, you can get its index easily using the indexOf function.
let index = numbers.indexOf(smallest);
1 Comment
abdulazeez
thank toy a lot but I'm learning and i want to know how it's work without using something like indexOf i could easily use it, Thx <3