Scala & Spark: Limitations of IntelliJ IDE's "Evaluate Expression" window -
i ran across unexpected behaviour in intelli j ideas (v.2016.2
) "evaluate expression" window:
while works, both compiled code , using "evaluate expression" window
val df1 = spark.read.json("/examples/src/main/resources/people.json") df1.columns.foreach(println) // outputs "age" , "name" console
another dataset[row]
(dataframe
) involves columns
generated expressions works compiled code, while in "evaluate expression" window following exception displayed:
com.intellij.debugger.engine.evaluation.evaluateexception: type mismatch can't assign org.apache.spark.sql.dataset scala.runtime.objectref
both dataframes of class class org.apache.spark.sql.dataset
. according intelli js documentation limitations are:
- a method can invoked within expression evaluation dialog if debugger has stopped @ breakpoint, has not been paused.
- expression evaluation can "single-level". in other words, if intellij idea stops @ breakpoint within method called expression evaluation, cannot use expression evaluation feature again.
- if method invoked within expression evaluation has breakpoint inside body, breakpoint ignored.
that apparently half truth.
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