Question

How to print the distinct elements of an array in TypeScript

Answer 1

function getUniqueElements(arr: number[]): number[] {
    const counts: { [key: number]: number } = {};

    arr.forEach((val) => {
        counts[val] = (counts[val] || 0) + 1;
    });

    const unique: number[] = [];
    for (const [key, value] of Object.entries(counts)) {
        if (value === 1) {
            unique.push(Number(key));
        }
    }

    return unique;
}

function printUniqueElements(arr: number[]): void {
    const unique = getUniqueElements(arr);
    
    unique.forEach((val) => console.log(val));
}

const arr: number[] = [3, 5, 9, 1, 7, 8, 1, 9, 0, 3, 9];

printUniqueElements(arr);



/*
run:
 
0
5
7
8
 
*/

 

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Answer 2

const array: number[] = [3, 5, 9, 1, 7, 8, 1, 9, 0, 3, 9];

const uniqueElements: number[] = array.filter((item, index, arr) => 
    arr.indexOf(item) === arr.lastIndexOf(item)
);

console.log(uniqueElements);

 
 
/*
run:
 
[5, 7, 8, 0] 
 
*/

 

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