Guide to tallying the occurrences of a specific key within an object array and attaching the count to each key's current value

Question

Guide to tallying the occurrences of a specific key within an object array and attaching the count to each key's current value

Is there a way to determine the number of occurrences of the 'value' key within an object that is part of an array, and then add the count to each value if applicable?

In this case, 'a' represents the original data

var a = [
    { id: 1, value: "10000"},
    { id: 2, value: "20000"},
    { id: 3, value: "30000"},
    { id: 4, value: "10000"},
    { id: 5, value: "20000"},
    { id: 6, value: "40000"},
    { id: 7, value: "10000"},
    { id: 8, value: "70000"}
]

The desired outcome is as follows:

result = [
    { id: 1, value: "10000"},
    { id: 2, value: "20000"},
    { id: 3, value: "30000"},
    { id: 4, value: "10000 (1)"},
    { id: 5, value: "20000 (1)"},
    { id: 6, value: "40000"},
    { id: 7, value: "10000 (2)"},
    { id: 8, value: "10000 (3)"}
]

javascript reactjs vue.js lodash underscore.js

Answer 1

Answer №1

Utilizing Array.map to iterate through the array and store the values.

In my opinion, this approach enhances readability compared to using Map.

const values = {},
  b = a.map(({ id, value }) => {
    values[value] = (values[value] || 0) + 1; // assigning and incrementing
    if (values[value] > 1) value += ` (${values[value]-1})`;
    return { id, value };
  });

console.log(b)

<script>
var a = [
    { id: 1, value: "10000"},
    { id: 2, value: "20000"},
    { id: 3, value: "30000"},
    { id: 4, value: "10000"},
    { id: 5, value: "20000"},
    { id: 6, value: "40000"},
    { id: 7, value: "10000"},
    { id: 8, value: "10000"}
]</script>

Answer 2

Utilizing Array.map to iterate through the array and store the values.

In my opinion, this approach enhances readability compared to using Map.

const values = {},
  b = a.map(({ id, value }) => {
    values[value] = (values[value] || 0) + 1; // assigning and incrementing
    if (values[value] > 1) value += ` (${values[value]-1})`;
    return { id, value };
  });

console.log(b)

<script>
var a = [
    { id: 1, value: "10000"},
    { id: 2, value: "20000"},
    { id: 3, value: "30000"},
    { id: 4, value: "10000"},
    { id: 5, value: "20000"},
    { id: 6, value: "40000"},
    { id: 7, value: "10000"},
    { id: 8, value: "10000"}
]</script>

Answer 3

Answer №2

Utilizing the Map object can be helpful in keeping track of the number of occurrences for each value.

const data = [
    { id: 1, value: '10000' },
    { id: 2, value: '20000' },
    { id: 3, value: '30000' },
    { id: 4, value: '10000' },
    { id: 5, value: '20000' },
    { id: 6, value: '40000' },
    { id: 7, value: '10000' },
    { id: 8, value: '70000' },
];

const valueMap = new Map();

const processedData = data.map((item) => {
    const count = valueMap.get(item.value);
    valueMap.set(item.value, (count ?? 0) + 1);
    return count ? { ...item, value: `${item.value} (${count})` } : item;
});

console.log(processedData);

Answer 4

Utilizing the Map object can be helpful in keeping track of the number of occurrences for each value.

const data = [
    { id: 1, value: '10000' },
    { id: 2, value: '20000' },
    { id: 3, value: '30000' },
    { id: 4, value: '10000' },
    { id: 5, value: '20000' },
    { id: 6, value: '40000' },
    { id: 7, value: '10000' },
    { id: 8, value: '70000' },
];

const valueMap = new Map();

const processedData = data.map((item) => {
    const count = valueMap.get(item.value);
    valueMap.set(item.value, (count ?? 0) + 1);
    return count ? { ...item, value: `${item.value} (${count})` } : item;
});

console.log(processedData);

Answer 5

Answer №3

var b = [
    { code: 1, amount: '10000' },
    { code: 2, amount: '20000' },
    { code: 3, amount: '30000' },
    { code: 4, amount: '10000' },
    { code: 5, amount: '20000' },
    { code: 6, amount: '40000' },
    { code: 7, amount: '10000' },
    { code: 8, amount: '10000' },
];

const valueMap = {};

const newArr = b.map((item) => {
    const tempVal = { ...item };
    if (!valueMap[item.amount]) {
        valueMap[item.amount] = 1;
    } else if (valueMap[item.amount]) {
        tempVal.amount = `${item.amount} (${valueMap[item.amount]})`;
        valueMap[item.amount] += 1;
    }
    return tempVal;
});

console.log(newArr);

Answer 6

var b = [
    { code: 1, amount: '10000' },
    { code: 2, amount: '20000' },
    { code: 3, amount: '30000' },
    { code: 4, amount: '10000' },
    { code: 5, amount: '20000' },
    { code: 6, amount: '40000' },
    { code: 7, amount: '10000' },
    { code: 8, amount: '10000' },
];

const valueMap = {};

const newArr = b.map((item) => {
    const tempVal = { ...item };
    if (!valueMap[item.amount]) {
        valueMap[item.amount] = 1;
    } else if (valueMap[item.amount]) {
        tempVal.amount = `${item.amount} (${valueMap[item.amount]})`;
        valueMap[item.amount] += 1;
    }
    return tempVal;
});

console.log(newArr);

Guide to tallying the occurrences of a specific key within an object array and attaching the count to each key's current value

Answer №1

Answer №2

Answer №3

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