可以尝试一下下面的代码:
def calcNewStockNum(dates, symbols){ d = dates.groups() sortedDates = d.keys().sort() dailyStocks = loop(x->symbols[d[x]].set(), sortedDates) newStockNum = eachPre(def(t2, t1)->size(t2 - t1), dailyStocks).flatten() return table(sortedDates as date, newStockNum) } calcNewStockNum(t.date, t.symbol)