wrappedArray$ofRef 无法转换为 scala.collection.immutable.Seq

Question

I'm trying to convert some Python code to Scala.

Python code:

def col_c(o_row_ids,n_row_ids):
    o_set=set(o_row_ids)
    n_set=set(n_row_ids)
    if o_set=n_set
        return "in"
    elif o_set < n_set:
        return "Me"
    elif n_set < o_set:
        return "Sp"
    return "SM"

Scala code:

def col_c: UserDefinedFunction = udf((o_row_ids:Seq[String], n_row_ids: Seq[String]) => {
    val o_set = o_row_ids.toSet.count(z => true) //set(o_row_ids)
    val n_set = n_row_ids.toSet.count(z=> true)
    if (o_set == n_set)
        "In"
    else if( o_set < n_set)
        "Me"
    else if (n_set < o_set)
        "Sp"
    else "SM"
})

But I'm getting the following error:

failed to execute user defined function(col_c(array(string),array(string)=>string scala.collection.mutable.wrappedArray$ofRef cannot be cast to scala.collection.immutable.Seq

Any suggestion how to prevent this error?

Answer 1

WrappedArray extends scala.collection.mutable.Seq which itself extends scala.collection.Seq .

Looks like you have imported scala.collection.immutable.Seq , thus the error.

One possibility to solve your issue is to type your UDF with inputs as scala.collection.Seq .