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我有DF <-(ID,Year,Sales)
,我想创建第四列LastYearSale
,选择去年的销售额。例如,如果有:去年同日销售
ID Year Sales
1 01/01/2015 50000
2 01/01/2014 20000
我想输出是这样的:
ID Year Sales LastYearSales
1 01/01/2015 50000 20000
2 01/01/2014 20000
试试'library(dplyr); DF%>%mutate(LastYearSales = lead(Sales))' – akrun