Example 1: how to get duplicate values from array in javascript
var array = [1, 2, 2, 3, 3, 4, 5, 6, 2, 3, 7, 8, 5, 22, 1, 2, 511, 12, 50, 22];
console.log([...new Set(
array.filter((value, index, self) => self.indexOf(value) !== index))]
);
Example 2: find duplicates and their count in an array javascript
var counts = {};
your_array.forEach(function(x) { counts[x] = (counts[x] || 0)+1; });
Example 3: how to get duplicate values from array in javascript
var input = [1, 2, 3, 1, 3, 1];
var duplicates = input.reduce(function(acc, el, i, arr) {
if (arr.indexOf(el) !== i && acc.indexOf(el) < 0) acc.push(el); return acc;
}, []);
document.write(duplicates);
Example 4: find duplicate in an array using xor
int DuplicateNumber(int arr[], int size){
int ans=0;
for(int i=0;i<size;i++){
ans= ans ^ arr[i] ;
}
for(int i=0;i<=size-2;i++){
ans= ans ^ i;
}
return ans;
}
Example 5: how to count duplicates in an array javascript
arr.reduce((b,c)=>((b[b.findIndex(d=>d.el===c)]||b[b.push({el:c,count:0})-1]).count++,b),[]);
Example 6: find duplicate in an array using xor
int DuplicateNumber(int arr[], int size){
int ans=0;
for(int i=0;i<size;i++){
ans= ans ^ arr[i] ;
}
for(int i=0;i<=size-2;i++){
ans= ans ^ i;
}
return ans;
}