How to get index of duplicate rows based on multiple columns javascript?

souradeep Misra 0
Viewed 33

I have the below array

const dummyData =[
{
"plateID":"1234567",
"freezer":"fridzer A",
"shelf":"1",
"box":"1",
"position":"1",
},
{
"plateID":"1234567",
"freezer":"fridzer B",
"shelf":"1",
"box":"1",
"position":"1",
},
{
"plateID":"1234567",
"freezer":"fridzer C",
"shelf":"12",
"box":"11",
"position":"13",
},
{
"plateID":"1234567",
"freezer":"fridzer A",
"shelf":"1",
"box":"1",
"position":"1",
},
{
"plateID":"1234567",
"freezer":"fridzer A",
"shelf":"5",
"box":"2",
"position":"3",
},
{
"plateID":"1234567",
"freezer":"fridzer C",
"shelf":"12",
"box":"11",
"position":"13",
},
]

I want to match "freezer","shelf","box","position" value and find the index of duplicate value.

The output will be like

[
  0,
  2,
  3,
  5
]

I have tried the below approach but only able to match one column at a time (Not all columns)

let duplicates = [];
let tempArray = {};

dummyData.forEach((item, index) => {

    tempArray[item.freezer] = tempArray[item.freezer] || [];

    tempArray[item.freezer].push(index);

});

for (var key in tempArray) {

    if (tempArray[key].length > 1) {

        duplicates = duplicates.concat(tempArray[key]);

    }

    console.log(duplicates);
    console.log(tempArray);
}

Is there ay way to match all four columns at a time and find the index of duplicate value ?

arrays typescript javascript
2 Answers

Hi You can use a find to verify if the object with the specific columns is already on the temp array or not, like this:

const dummyData = [
    {
        plateID: "1234567",
        freezer: "fridzer A",
        shelf: "1",
        box: "1",
        position: "1",
    },
    {
        plateID: "1234567",
        freezer: "fridzer B",
        shelf: "1",
        box: "1",
        position: "1",
    },
    {
        plateID: "1234567",
        freezer: "fridzer C",
        shelf: "12",
        box: "11",
        position: "13",
    },
    {
        plateID: "1234567",
        freezer: "fridzer A",
        shelf: "1",
        box: "1",
        position: "1",
    },
    {
        plateID: "1234567",
        freezer: "fridzer A",
        shelf: "5",
        box: "2",
        position: "3",
    },
    {
        plateID: "1234567",
        freezer: "fridzer C",
        shelf: "12",
        box: "11",
        position: "13",
    },
];

let duplicates = [];
let tempArray = [];

dummyData.forEach((element, key) => {
    let isAlreadyAdded = tempArray.find(
        (item) =>
            item.freezer === element.freezer && item.shelf === element.shelf
    );

    if (!isAlreadyAdded) {
        tempArray.push(element);
    } else {
        duplicates.push(key);
    }
});

console.log(duplicates, tempArray);

Carlos Gutierrez0

From my understanding, you'll need to compare every element with every other element in the array of objects

here's my approach,

const dummyData =[
{
"plateID":"1234567",
"freezer":"fridzer A",
"shelf":"1",
"box":"1",
"position":"1",
},
{
"plateID":"1234567",
"freezer":"fridzer B",
"shelf":"1",
"box":"1",
"position":"1",
},
{
"plateID":"1234567",
"freezer":"fridzer C",
"shelf":"12",
"box":"11",
"position":"13",
},
{
"plateID":"1234567",
"freezer":"fridzer A",
"shelf":"1",
"box":"1",
"position":"1",
},
{
"plateID":"1234567",
"freezer":"fridzer A",
"shelf":"5",
"box":"2",
"position":"3",
},
{
"plateID":"1234567",
"freezer":"fridzer C",
"shelf":"12",
"box":"11",
"position":"13",
},
]
let duplicates = new Set()
for(let i = 0; i< dummyData.length; i++){
    for(let j = i+1; j< dummyData.length; j++){
        if(JSON.stringify(dummyData[i]) == JSON.stringify(dummyData[j])){
            duplicates.add(i);
            duplicates.add(j);
        }
    }
}
console.log(Array.from(duplicates));

Output:

[ 0, 3, 2, 5 ]
Josal0
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