android - Swift 在 Kotlin 中的 replaceSubrange

Question

什么是实现类似 Swift 的优雅方式:

sections.replaceSubrange(sectionIndex ..< (sectionIndex + 1), with: [section])

在 Kotlin 中？

到目前为止我的代码:

var filters = BehaviorRelay.create<List<FilterSection>>()

 fun updateFilters(type: FilterType, filtersArray: List<Filter>, state: SectionState = SectionState.Loaded){
        val sectionIndex = filters.value.indexOfFirst { it.filterType == type }
        val section =  filters.value[sectionIndex].update(state, filtersArray)
        val sections = filters.value
        //here is where I need to replace the elements
        filters.accept(sections)
    }

Answer 1

标准库中没有内置函数。但是，您可以按如下方式定义扩展:

fun <T> List<T>.replaceSubrange(subrange: IntRange, withItems: List<T>): List<T> =
    take(subrange.first) + withItems + drop(subrange.endInclusive + 1)

> listOf(1, 2, 3, 4, 5).replaceSubrange(1..3, listOf(0, 0, 0, 0))
[1, 0, 0, 0, 0, 5]

或者，如果您只需要将子列表插入到列表中:

fun <T> List<T>.insertSubrangeAt(index: IntRange, items: List<T>): List<T> =
    take(atIndex) + items + drop(atIndex)

> listOf(1, 2, 3, 4, 5).insertSubrangeAt(1, listOf(0, 0, 0, 0))
[1, 0, 0, 0, 0, 2, 3, 4, 5]