wrappedArray$ofRef cannot be cast to 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.