Scala 在中列出多个匿名/下划线参数以供理解

Scala 在中列出多个匿名/下划线参数以供理解,scala,functional-programming,for-comprehension,doobie,Scala,Functional Programming,For Comprehension,Doobie,我是Scala/functional的新手,所以我还不能使用技术语言 我的理解能力有问题 val queries = for { _ <- createBanco _ <- createBancoMedio bankInsertions <- Update[Banco](insertStr).updateMany(NonEmptyList.fromList(createBankList(1, maxBanks)).get) mediumInsertions

我是Scala/functional的新手,所以我还不能使用技术语言

我的理解能力有问题

 val queries =
for {
  _ <- createBanco
  _ <- createBancoMedio
  bankInsertions  <- Update[Banco](insertStr).updateMany(NonEmptyList.fromList(createBankList(1, maxBanks)).get)
  mediumInsertions  <- Update[BancoMedio](mediumInsert).updateMany(NonEmptyList.fromList(mediumList).get)
  bankCount <- BancoStatements.getCount().unique
  bankGetIds <- BancoStatements.getIds(0, maxBanks).to[List]
  bankSome <- BancoStatements.getSome(halfBanks).to[List]
} yield (bankCount, bankGetIds, bankSome)

//Execute database queries, saves them on tuple
val transactionResults : (Int, List[String], List[Banco]) = 
queries.transact(h2Transactor).unsafeRunSync()
val查询=
为了{

_刚刚解决了这个问题,又做了一次,以便理解列表

val createList = for {
  m <- createBancoMedio
  b <- createBanco
} yield List(b, m)

val queries =
for {
  _ <- createList ....
val createList=for{

m如果
G
有一个
Applicative
实例,则可以使用
.sequence
列表[G[a]]
转换为
G[a]
,其中
ConnectionIO执行以下操作:

val queries =
for {
  _ <- List(createBanco, createBancoMedio).sequence
  ...
val查询=
为了{

_我必须在序列中指定G和A,但工作起来很有魅力。谢谢!(.sequence[conctionio,Int])