topBottomN function will will grab the top N percent or botom N percent of values of a column and return it in a H2OFrame.
h2o.topBottomN(x, column, nPercent, grabTopN)
An H2OFrame with 2 columns: first column is the original row indices, second column contains the values
an H2OFrame
is a column name or column index to grab the top N percent value from
a top percentage values to grab
if -1 grab bottom percentage, 1 grab top percentage