In-depth analysis of JavaScript's group sum operation

Javascript is a powerful programming language with numerous data processing and calculation functions. Among them, group summation is an important function that can help us conduct in-depth analysis and processing of complex data.

We can use the array method in Javascript to perform group sum operations. For example, we have an array containing multiple sets of data, each set of data contains a name and corresponding value. Now we want to group this data by name and calculate the total value of each group.

First, we can use the reduce method in Javascript to group the data. The reduce method can traverse the array and use an accumulator to record the grouping of the data. Next, we can define an empty object to save the grouped data:

const data = [
  { name: "Group A", value: 10 },
  { name: "Group B", value: 15 },
  { name: "Group A", value: 20 },
  { name: "Group B", value: 25 },
  { name: "Group C", value: 30 },
];

const groupedData = data.reduce((acc, cur) => {
  if (!acc[cur.name]) {
    acc[cur.name] = [];
  }
  acc[cur.name].push(cur.value);
  return acc;
}, {});

After executing the above code, we will get an object containing the grouped data:

{
  "Group A": [10, 20],
  "Group B": [15, 25],
  "Group C": [30]
}

Next , we can use the map method in Javascript to sum the grouped data. The map method can traverse the array and perform the specified operation on each element. Here, we sum each grouped data array and store the result in a new array:

const summedGroups = Object.keys(groupedData).map((groupName) => {
  const groupValues = groupedData[groupName];
  const sum = groupValues.reduce((acc, cur) => acc + cur);
  return { name: groupName, value: sum };
});

After executing the above code, we will get an array containing the grouped summed data:

[
  { name: "Group A", value: 30 },
  { name: "Group B", value: 40 },
  { name: "Group C", value: 30 }
]

Finally, we can output the results or use them in other ways. The complete code is as follows:

const data = [
  { name: "Group A", value: 10 },
  { name: "Group B", value: 15 },
  { name: "Group A", value: 20 },
  { name: "Group B", value: 25 },
  { name: "Group C", value: 30 },
];

const groupedData = data.reduce((acc, cur) => {
  if (!acc[cur.name]) {
    acc[cur.name] = [];
  }
  acc[cur.name].push(cur.value);
  return acc;
}, {});

const summedGroups = Object.keys(groupedData).map((groupName) => {
  const groupValues = groupedData[groupName];
  const sum = groupValues.reduce((acc, cur) => acc + cur);
  return { name: groupName, value: sum };
});

console.log(summedGroups);

Through the above code, we can easily perform group sum operations on arrays in Javascript, thereby achieving more efficient data processing and calculations.

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