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我希望不同组的前一行值。我已经通过了解决方案here,并尝试了下面显示的代码。按组别划分的R行数值
new_data[,avg_week := shift(.(avg_travel_time),type = "lag"), by = identifier]
这是我得到的错误。
Error in `[.data.frame`(new_data, , `:=`(avg_week, c(NA, avg_travel_time[-.N])), :
unused argument (by = identifier)
你有一个错字之前先转换为
data.table
(setDT(new_data)
不需要'(''内'shift' NEW_DATA [,avg_week:=移(avg_travel_time,TYPE =“滞后“),由=标识符]' – akrun还是一样的错误“> NEW_DATA [,avg_week:=移(avg_travel_time,类型= ”滞后“),由=标识符] 错误'[.data.frame'(NEW_DATA, ,':='(avg_week,shift(avg_travel_time,: unused argument(by = identifier)' – cutepanda