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javascriptarrays
Arturs Golis
Arturs Golis

Reputation: 29

JavaScript MinValue

I need find the minimum value from a two-dimensional array. But something goes wrong, someone can explain me please?

let array = [
  [20, 34, 2],
  [9, 12, 18],
  [3, 4, 5]
];


let str = array.join(",");
console.log(str);

let array_2 = str.split(",");
console.log(array_2);


let minValue = array_2[0];
for (let i = 0; i < array_2.length; i++) {
    if (array_2[i] < minValue) {
      minValue = array_2[i];
    }
}
console.log(minValue);

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Upvotes: 1

Views: 67

Answers (3)

Aalexander
Aalexander

Reputation: 5004

Convert your Strings to Number before the comparison

 let array = [
  [20, 34, 2],
  [9, 12, 18],
  [3, 4, 5]
];


let str = array.join(",");
console.log(str);
//here you convert to number
let array_2 = str.split(",").map(Number);
console.log(array_2);

Initialize minValue with the highest possible value

you should use Number.MAX_VALUE;

let minValue = Number.MAX_VALUE;

All together

let array = [
    [20, 34, 2],
    [9, 12, 18],
    [3, 4, 5]
  ];
  
  let str = array.join(",");
  console.log(str);
  
  let array_2 = str.split(",").map(Number);
  console.log(array_2);
  
  
  let minValue = Number.MAX_VALUE;
  for (let i = 0; i < array_2.length; i++) {
      if (array_2[i] < minValue) {
        minValue = array_2[i];
      }
  }
  console.log(minValue);

Upvotes: 0

Nina Scholz
Nina Scholz

Reputation: 386530

The canonical way is to flatten the array with Array#flat and get the minimum with Math.min by spreading the values (spread syntax ...).

let array = [[20, 34, 2], [9, 12, 18], [3, 4, 5]];

console.log(Math.min(...array.flat()));

Upvotes: 2

Unmitigated
Unmitigated

Reputation: 89139

You need to convert the strings to numbers so that numerical comparison is used instead of lexicographical comparison.

let array = [
  [20, 34, 2],
  [9, 12, 18],
  [3, 4, 5]
];


let str = array.join(",");
console.log(str);

let array_2 = str.split(",").map(Number);//convert to number
console.log(array_2);


let minValue = array_2[0];
for (let i = 0; i < array_2.length; i++) {
    if (array_2[i] < minValue) {
      minValue = array_2[i];
    }
}
console.log(minValue);

Alternatively, you could use Array#flat on the original array so that you do not need to join and split.

let array = [
  [20, 34, 2],
  [9, 12, 18],
  [3, 4, 5]
];
let array_2 = array.flat();
console.log(array_2);
let minValue = array_2[0];
for (let i = 0; i < array_2.length; i++) {
    if (array_2[i] < minValue) {
      minValue = array_2[i];
    }
}
console.log(minValue);

Upvotes: 2

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