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Core Map

docs/data/core-map.md

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Original Source

Transforms each element in a slice to a new type using a function. Takes both the element and its index, making it useful for transformations that need positional context.

go
// Basic type transformation
transformed := lo.Map([]int64{1, 2, 3, 4}, func(x int64, index int) string {
    return strconv.FormatInt(x, 10)
})
// transformed: []string{"1", "2", "3", "4"}
go
// Transforming structs
type Person struct {
    FirstName string
    LastName  string
    Age       int
}

people := []Person{
    {FirstName: "John", LastName: "Doe", Age: 25},
    {FirstName: "Jane", LastName: "Smith", Age: 30},
}

fullNames := lo.Map(people, func(p Person, index int) string {
    return fmt.Sprintf("%s %s", p.FirstName, p.LastName)
})
// fullNames: []string{"John Doe", "Jane Smith"}