DataFrame filter is not handling float/double with Scientific Notation 'e' / 'E'

In DataFrames filter operation,when giving float comparison with e (2.0e2) it is not converting the comparison constant as expected (200.0 in this case).
For example:

val df = sqlContext.createDataFrame(Seq(("a",1.0),("b",2.0),("c",3.0)))
df.filter("_2 < 2.0e1").show()

+--+---+
|_1| _2|
+--+---+
| a|1.0|
+--+---+ 

It should return all the three records from the dataframe,but is return record which is less than 2.0.
It seems it is just comparing with the mantissa/coefficient.

On the other hand,sqlContext is handling the above case and giving the desired output.

df.resgisterTempTable("df")
sqlContext.sql("select * from df where `_2` < 2.0e1").show()

+--+---+
|_1| _2|
+--+---+
| a|1.0|
| b|2.0|
| c|3.0|
+--+---+