Pushing a series of Scala map operations into a separate list -

was tinkering translating java module scala , thought learning exercise on maps/placeholders... there way translate essence of code block single (map?) statement? (this i've come far scala-ized version)

dataproclist foreach (processor => { // #1   val fieldname: string = processor.getwritecolumn // #2   val sqlvalue: string = processor.getsqlvalue(hashmapoffieldvaluepairs.get(fieldname)) // #3   sqlcolumnvaluepair += ((fieldname, sqlvalue)) // #4 }) 

in short:

1. a list of dataprocessor(s) iterated
2. from each dp, string extracted (call "alpha")
3. alphpa used look-up key (externally defined) hashmap, gets/returns sql-prep'd value (call "zed")
4. alpha , zed paired , appended own list/hash/set/whatever (called "sqlcolumnvaluepair")

those lines have been expanded readability; , portions distilled down using various map-ings (for example 1 & 2), there way in using single statment? feels should able condense down far...but don't have enough scala experience map-ings/placeholders know if fruitless endeavor, or not.

tia.

(note: found answer post pretty educational summary on scala's map operations: functional programming, scala map , fold left)

edit: removed .getorelse() operation original example, think distraction core problem.

edit 2: after consideration, maybe better way phrase learning objective here be: "how duplicate functionality using fewest number of operations." (which had assumed combination of map operations, partial functions, , forth.) , in doing so, gain broader understanding of set of scala classes/operators can used in similar situations.

you comprehension (and idiomatic way it):

for {   processor <- dataproclist   fieldname = processor.getwritecolumn   fieldvalue <- hashmapoffieldvaluepairs.get(fieldname) } yield (fieldname -> processor.getsqlvalue(fieldvalue)) 

this amounts to: each processor, write column, in field-value hashmap (get option), each value in option (either 1 or 0 values), yield (roughly: add growing sequence of result values) pair fieldname , corresponding sqlvalue, if any.

note in case, there no getorelse call, such - if there isn't entry in hash map given field name, no (fieldname, sqlvalue) pair generated processor. final result have values filtered out (which may or may not match semantics after).