数据表中的子集
问题描述：
我试图将data.table子集（从包 data.table ）in R（not a data.frame）。我有一个4位数年作为关键。我想通过采取一系列的年子集。
I am trying to subset a data.table ( from the package data.table ) in R (not a data.frame). I have a 4 digit year as a key. I would like to subset by taking a series of years. For example, I want to pull all the records that are from 1999, 2000, 2001.
我已经尝试传入我的 DT [J年）] 二进制搜索语法如下：
I have tried passing in my DT[J(year)] binary search syntax the following:
1999,2000,2001
c(1999,2000,2001)
1999, 2000, 2001
工作。
答
什么工作对于任何人都知道如何做一个子集，你想选择的年份不只是1， data.frame 适用于 data.table 。
What works for data.frames works for data.tables.
subset(DT, year %in% 1999:2001)