I have List collection with data below:
case class Expense_detail(po_id: Long, supplier_id: String, price: String)
Expense_detail(1,"S00001","1000.0"),
Expense_detail(2,"S00001","2000.0"),
Expense_detail(3,"S00002","3,000.0"),
Expense_detail(4,"S00003","4,000.0")
Is it possible to map it into below Map collection:
"S00001" -> ((1,2), "3000.0")
"S00002" -> ((3), "3000.0")
"S00003" -> ((4), "4000.0")
Yes with groupBy an mapValues.
case class ExpenseDetail(poId: Long, supplierId: String, price: String)
val details : List[ExpenseDetail] = ...
details.
groupBy( _.supplierId ).
mapValues( details => ( (details.map(_.poId)), details.map(_.price.toInt).sum ))
This should work.
I changed the naming to honor the Scala/Java best practices to use CamelCase instead of snake_case.
Related
I need to change from one List[String] to List[MyObject] in scala.
For example,JSON input is like below
employee: {
name: "test",
employeeBranch: ["CSE", "IT", "ECE"]
}
Output should be like this,
Employee: {
Name: "test",
EmployeeBranch:[{"branch": "CSE"}, {"branch": "IT"}, {"branch": "ECE"}]
}
Input case class:
Class Office(
name: Option[String],
employeeBranch: Option[List[String]])
Output case class:
Class Output(
Name: Option[String],
EmployeeBranch: Option[List[Branch]])
case class Branch(
branch: Option[String])
This is the requirement.
It is hard to answer without knowing details of the particular JSON library, but an Object is probably represented as a Map. So to convert a List[String] to a List[Map[String, String]] you can do this:
val list = List("CSE", "IT", "ECE")
val map = list.map(x => Map("branch" -> x))
This gives
List(Map(branch -> CSE), Map(branch -> IT), Map(branch -> ECE))
which should convert to the JSON you want.
I want to parse province to case class, it throws mismatch
scala.MatchError: Some(USA) (of class scala.Some)
val result = EntityUtils.toString(entity,"UTF-8")
val address = JsonParser.parse(result).extract[Address]
val value.province = Option(address.province)
val value.city = Option(address.city)
case class Access(
device: String,
deviceType: String,
os: String,
event: String,
net: String,
channel: String,
uid: String,
nu: Int,
ip: String,
time: Long,
version: String,
province: Option[String],
city: Option[String],
product: Option[Product]
)
This:
val value.province = Option(address.province)
val value.city = Option(address.city)
doesn't do what you think it does. It tries to treat value.province and value.city as extractors (which don't match the type, thus scala.MatchError exception). It doesn't mutate value as I believe you intended (because value apparently doesn't have such setters).
Since value is (apparently) Access case class, it is immutable and you can only obtain an updated copy:
val value2 = value.copy(
province = Option(address.province),
city = Option(address.city)
)
Assuming the starting point:
val province: Option[String] = ???
You can get the string with simple pattern matching:
province match {
case Some(stringValue) => JsonParser.parse(stringValue).extract[Province] //use parser to go from string to a case class
case None => .. //maybe provide a default value, depends on your context
}
Note: Without knowing what extract[T] returns it's hard to recommend a follow-up
In Scala, is there a way to map over a collection while passing a value along fold-style? Something like:
case class TxRecord(name: String, amount: Int)
case class TxSummary(name: String, amount: Int, balance: Int)
val txRecords: Seq[TxRecord] = txRecordService.getSortedTxRecordsOfUser("userId")
val txSummarys: Seq[TxSummary] = txRecords.foldMap(0)((sum, txRecord) =>
(sum + txRecord.amount, TxSummary(txRecord.name, txRecord.amount, sum + txRecord.amount)))
case class Venue(#Key("_id") id: Int,
location: Tuple2[Double, Double],
name: String)
object VenueDAO extends SalatDAO[Venue, Int](collection = MongoConnection()("ec")("venue"))
VenueDAO.find(?) //return Option[Venue]
How to search data by location using Salat?
Two things to start out:
Per the README.txt, Salat doesn't support Tuples.
Perhaps you are thinking of Mongo's Geospatial coordinate support?
In any case, since Salat doesn't support Tuples, here is what you can do:
case class Location(x: Double, y: Double)
case class Venue(#Key("_id") id: Int, location: Location, name, String)
val venue = Venue(1, Location(1.0, 1.0), "NYC")
VenueDAO.save(venue)
println(s"Saved: $venue")
val found = VenueDAO.findOne(MongoDBObject("location.x" -> 1.0, "location.y" -> 1.0))
println(s"Found: $found")
Prints:
Saved: Venue(1,Location(1.0,1.0),NYC)
Found: Some(Venue(1,Location(1.0,1.0),NYC))
I was able to perform simple validations on simple json structures like this one:
object RestTest extends Controller {
case class Address(street: String,
number: Int)
case class Person(name: String,
age: Int,
address: Address)
implicit val address = Json.reads[Address]
implicit val rds = Json.reads[Person]
def restTest = Action(parse.json) {
request =>
request.body.validate[Person].map {
case person => Ok(Json.obj("e" -> 0, "message" -> ("The name is: " + person.name + " and he lives in " + person.address.street)))
}.recoverTotal(e => Ok("e" -> 1)
}
}
Now I have the following structure that contains arrays, but I wasn't able to validate it correctly so far. I have tried many different ways, but I keep receiving compilation errors.
case class SecondStructure(index: Int)
case class EntryStructure(field1: String,
muSecondJsonArray: List[SecondStructure])
case class MyJsonArray(allEntries: List[EntryStructure])
How can I validate this json?
Thanks
First of all, ensure you are using the latest Play 2.1.1 releases. There was an issue with earlier versions when validating case classes with a single field. After that, it should all work - please see below for an example:
object JsonTest {
case class SecondStructure(index: Int)
case class EntryStructure(field1: String, muSecondJsonArray: List[SecondStructure])
case class MyJsonArray(allEntries: List[EntryStructure])
// Use the macro "inception" feature to automatically build your Readers.
implicit val ssReads = Json.reads[SecondStructure]
implicit val esReads = Json.reads[EntryStructure]
implicit val arrayReads = Json.reads[MyJsonArray]
// Defining an example instance...
val testArray = MyJsonArray(
List(
EntryStructure("foo", List(SecondStructure(1), SecondStructure(2))),
EntryStructure("bar", List(SecondStructure(3), SecondStructure(4)))))
// And the equivilant JSON structure...
val testJson = Json.obj("allEntries" ->
Json.arr(
Json.obj("field1" -> "foo", "muSecondJsonArray" -> Json.arr(
Json.obj("index" -> 1), Json.obj("index" -> 2))),
Json.obj("field1" -> "bar", "muSecondJsonArray" -> Json.arr(
Json.obj("index" -> 3), Json.obj("index" -> 4)))))
testJson.validate[MyJsonArray].map {
case foo if foo == testArray => println("Okay, we're good!")
}
}