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GroupBy

func GroupBy[T any, K comparable](slice []T, keySelector func(T) K) map[K][]T

GroupBy groups elements of a slice by a key extracted using the keySelector function. Returns a map where keys are the grouping keys and values are slices of elements that share that key. This is a LINQ-style operation useful for categorizing or organizing data.

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package main

import (
    "fmt"

    "github.com/Goldziher/go-utils/sliceutils"
)

func main() {
    type User struct {
        Name string
        Age  int
    }

    users := []User{
        {"Alice", 30},
        {"Bob", 25},
        {"Charlie", 30},
        {"David", 25},
    }

    // Group users by age
    byAge := sliceutils.GroupBy(users, func(u User) int {
        return u.Age
    })

    fmt.Printf("%v\n", byAge)
    // map[25:[{Bob 25} {David 25}] 30:[{Alice 30} {Charlie 30}]]
}