Array.crosstab(RowSet, ColSet,PageSet,DataSet)
Returns a simple cross tabulation of two or more factors. By default computes a frequency table of the factors unless an array of values and an aggregation function are passed.
[[100,2,2],[101,4,5],[102,6,7]].crosstab()
[[100,2,2],[101,4,5],[102,6,7]].uncrosstab()