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package lo
import "golang.org/x/exp/constraints"
// Range creates an array of numbers (positive and/or negative) with given length.
// Play: https://go.dev/play/p/0r6VimXAi9H
func Range(elementNum int) []int {
length := If(elementNum < 0, -elementNum).Else(elementNum)
result := make([]int, length)
step := If(elementNum < 0, -1).Else(1)
for i, j := 0, 0; i < length; i, j = i+1, j+step {
result[i] = j
}
return result
}
// RangeFrom creates an array of numbers from start with specified length.
// Play: https://go.dev/play/p/0r6VimXAi9H
func RangeFrom[T constraints.Integer | constraints.Float](start T, elementNum int) []T {
length := If(elementNum < 0, -elementNum).Else(elementNum)
result := make([]T, length)
step := If(elementNum < 0, -1).Else(1)
for i, j := 0, start; i < length; i, j = i+1, j+T(step) {
result[i] = j
}
return result
}
// RangeWithSteps creates an array of numbers (positive and/or negative) progressing from start up to, but not including end.
// step set to zero will return empty array.
// Play: https://go.dev/play/p/0r6VimXAi9H
func RangeWithSteps[T constraints.Integer | constraints.Float](start, end, step T) []T {
result := []T{}
if start == end || step == 0 {
return result
}
if start < end {
if step < 0 {
return result
}
for i := start; i < end; i += step {
result = append(result, i)
}
return result
}
if step > 0 {
return result
}
for i := start; i > end; i += step {
result = append(result, i)
}
return result
}
// Clamp clamps number within the inclusive lower and upper bounds.
// Play: https://go.dev/play/p/RU4lJNC2hlI
func Clamp[T constraints.Ordered](value T, min T, max T) T {
if value < min {
return min
} else if value > max {
return max
}
return value
}
// Sum sums the values in a collection. If collection is empty 0 is returned.
// Play: https://go.dev/play/p/upfeJVqs4Bt
func Sum[T constraints.Float | constraints.Integer | constraints.Complex](collection []T) T {
var sum T = 0
for _, val := range collection {
sum += val
}
return sum
}
// SumBy summarizes the values in a collection using the given return value from the iteration function. If collection is empty 0 is returned.
// Play: https://go.dev/play/p/Dz_a_7jN_ca
func SumBy[T any, R constraints.Float | constraints.Integer | constraints.Complex](collection []T, iteratee func(item T) R) R {
var sum R = 0
for _, item := range collection {
sum = sum + iteratee(item)
}
return sum
}
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