WebKotlin笔记函数式编程API（十）Kotlin笔记数据类型（一） Kotlin笔记字符串（二） Kotlin笔记运算符（三） Kotlin笔记函数（四） Kotlin笔记面向对象（五） Kotlin笔记继承、抽象类、接口（六） Kotlin笔记高阶函数（七） Kotlin笔记泛型（八） Kotlin 笔记 数据容器（九）文章目录Kotlin笔记函数式编程API（十 ...

firstOrNull - Kotlin Programming Language

WebMY FIRST BECON IN NULL SMP 😎😱 EP29-------------------------------------------------------------------------------------------------------------------------... WebOct 13, 2024 · Kotlin firstOrNullの使い方について. //以下のようなlistがあった場合に頭の1を取得したい場合に`firstOrNull`や`first`を使います val list = listOf ("1", "2", "3","1") … grams to molecules practice

redis实现存储帖子的点赞状态和数量

WebIt will print : Month(name=April, days=30, index=1) null Month(name=January, days=31, index=3) The first and the second objects are the same because we have only one April Month object and no February Month objects. But we have two Month objects with name January and days 31. findLast will return the last element i.e. the object with index = 3. WebFeb 8, 2024 · Some of them have additional variations to work with how Kotlin has differences – there is first() and firstOrNull(), where first throws if the collection is empty, but returns a non-nullable type otherwise. The interesting case is collect. Java 8 uses this to be able to collect all Stream elements to some collection using a provided strategy. Web2 days ago · User::all() can return an empty Collection if the Database table is empty, or if User uses the softDeletes trait and all rows have deleted_at set to a value.->first() can return null (but never an empty Collection) if nothing matches the supplied where() clause, or the table is empty or all deleted.::find(1) is shorthand for ->where('id', 1)->first(), so same rule … grams to moles argon