Signature Description Parameters
#include <DataFrame/DataFrameStatsVisitors.h>

template<typename T, typename I = unsigned long>
struct StatsVisitor;
        
This functor class calculates the following statistics of a given column; mean, variance, standard deviation, skew, and kurtosis. T: Column data type.
I: Index type.
    std::cout << "\nTesting Stats Visitor ..." << std::endl;

    StatsVisitor<double>    stats_visitor;

    df.visit<double>("dbl_col", stats_visitor);
    dvec = df.get_column<double> ("dbl_col");
    assert(fabs(stats_visitor.get_skew() - 0.0396307) < 0.0001);
    assert(fabs(stats_visitor.get_kurtosis() - -1.273) < 0.0001);
    assert(fabs(stats_visitor.get_mean() - 4.83406) < 0.0001);
    assert(fabs(stats_visitor.get_variance() - 6.58781) < 0.0001);