How to use Golang to implement classification summation

In computer programming, classification summation is a common problem, that is, classifying a set of numbers according to their attributes and summing the numbers within each category. This problem has applications in many fields, such as statistics, data mining, data analysis, etc. In this article, we will introduce how to implement categorical summation using Golang.

First, we need to define a data structure to represent a number, containing two attributes, namely value and category. In Golang, we can use structures to implement this data structure. The code is as follows:

type Data struct {
    value float64
    category string
}

Next, we need to create a function to classify the input set of data according to its category and classify each Sum the numbers within a category. This function should accept a list of data as input and return a dictionary where the keys are categories and the values ​​are the sum of the numbers within that category. In Golang, we can use the map type to implement this dictionary. The code is as follows:

func sumByCategory(dataList []Data) map[string]float64 {
    sumsByCategory := make(map[string]float64)
    for _, data := range dataList {
        sumsByCategory[data.category] += data.value
    }
    return sumsByCategory
}

This function first creates an empty map to save the sum of the numbers in each category. Then, iterate through the input data list and add each number to the sum of the corresponding category. Finally, return the map that holds the sum of the numbers within each category.

The following is a complete sample program for testing the function we implemented above:

package main

import "fmt"

type Data struct {
    value float64
    category string
}

func sumByCategory(dataList []Data) map[string]float64 {
    sumsByCategory := make(map[string]float64)
    for _, data := range dataList {
        sumsByCategory[data.category] += data.value
    }
    return sumsByCategory
}

func main() {
    dataList := []Data{
        {2.0, "A"},
        {3.2, "B"},
        {4.5, "C"},
        {1.8, "A"},
        {2.3, "B"},
        {5.1, "C"},
    }

    sumsByCategory := sumByCategory(dataList)
    fmt.Println(sumsByCategory)
}

Running this program will output the following results:

map[A:3 B:5.5 C:9.6]

This result shows that, Our categorical sum function correctly sorts the input data into its categories and sums the numbers within each category.

Finally, it should be noted that in actual problems, the data may be very large and cannot all be stored in memory. In this case, we can use an external sorting algorithm to sort the data into pieces and then perform classification and summation. This algorithm will involve more Golang built-in functions and external libraries, and is beyond the scope of this article.

In short, classification summation is a common problem and is very easy to implement in Golang. Using Golang's struct and map types, we can easily classify a set of data according to its attributes and sum the numbers within each category.

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