slices/filter.go

package slices

func Filter[T any](slice []T, f func(T) bool) []T {
	ret := make([]T, 0, len(slice))
	for _, v := range slice {
		if f(v) {
			ret = append(ret, v)
		}
	}
	return ret
}

func FindFirst[T any](slice []T, f func(T) bool) (T, bool) {
	for _, v := range slice {
		if f(v) {
			return v, true
		}
	}
	return *new(T), false
}

func FindFirstIndex[T any](slice []T, f func(T) bool) (int, bool) {
	for i, v := range slice {
		if f(v) {
			return i, true
		}
	}
	return -1, false
}

func FindLastIndex[T any](slice []T, f func(T) bool) (int, bool) {
	for i := len(slice); i >= 0; i-- {
		if f(slice[i]) {
			return i, true
		}
	}
	return -1, false
}