相关疑难解决方法(0)

我有类似这样的数据:

dt <- structure(list(fct = structure(c(1L, 2L, 3L, 4L, 3L, 4L, 1L, 2L, 3L, 1L, 2L, 3L, 2L, 3L, 4L), .Label = c("a", "b", "c", "d"), class = "factor"), X = c(2L, 4L, 3L, 2L, 5L, 4L, 7L, 2L, 9L, 1L, 4L, 2L, 5L, 4L, 2L)), .Names = c("fct", "X"), class = "data.frame", row.names = c(NA, -15L))

我想根据fct变量中的值从这个数据框中选择行.例如,如果我希望选择包含"a"或"c"的行,我可以这样做:

dt[dt$fct == 'a' | dt$fct == 'c', ]

产量

1    a 2
3    c 3
5    c 5
7    a …