freqtable

using DataFrames,DataFramesMeta, FreqTables
n=1000_000
y=ASCIIString[string("id",i) for i in rand(1:10,n)];
x=rand(1:10,n);
@time pda=PooledDataArray(y,UInt8);

@time f=freqtable(x);
@time f=freqtable(y);
@time f=freqtable(pda);
@time f=freqtable(x, pda);

d=DataFrame(x=P(x),y=P(y),pda=pda);
@time @by(d, :x, N=length(:x));
@time @by(d, :y, N=length(:x));
@time @by(d, :pda, N=length(:x));
@time @by(d, (:x, :pda), N=length(:x));