我有一个data.table,看起来像这样:
> dt <- data.table(
group1 = c("a", "a", "a", "b", "b", "b", "b"),
group2 = c("x", "x", "y", "y", "z", "z", "z"),
data1 = c(NA, rep(T, 3), rep(F, 2), "sometimes"),
data2 = c("sometimes", rep(F,3), rep(T,2), NA))
> dt
group1 group2 data1 data2
1: a x NA sometimes
2: a x TRUE FALSE
3: a y TRUE FALSE
4: b y TRUE FALSE
5: b z FALSE TRUE
6: b z FALSE TRUE
7: b z sometimes NA
我的目标是找到每个数据列中的非NA记录数,按group1 …
我在数据表中有一组五列.
dt <- data.table(
city = c(rep(1,2), rep(2,2), rep(3,2), rep(4,2)),
neighborhoods.1 = c(NA, "a", "b", "c", NA, NA, "d", "e"),
neighborhoods.2 = c(NA, "f", "g", rep(NA,5)),
neighborhoods.3 = c(NA, "h", rep(NA, 6)),
irrelevantdata = c(1:8)
)
city neighborhoods.1 neighborhoods.2 neighborhoods.3 irrelevantdata
1: 1 NA NA NA 1
2: 1 a f h 2
3: 2 b g NA 3
4: 2 c NA NA 4
5: 3 NA NA NA 5
6: 3 NA NA NA 6
7: 4 d …我有一项调查得出的数据，对于该问题的任何回答都被认为是有效的，无论是回答之前还是之后的问题。
所有用于响应的数据都在data.table中，其名称以“ question”开头的列中
> dt.x <- data.table(
row = 1:5,
question_a = c(NA,NA,"A","B","C"),
question_b = c(NA,"A","B","C","D")
)
> dt.x
row question_a question_b
1: 1 <NA> <NA>
2: 2 <NA> A
3: 3 A B
4: 4 B C
5: 5 C D
我的目标是删除以“问题”开头的任何列中都没有数据的行，但是其他列中可能有数据，例如示例中的行列。
row question_a question_b
1: 2 <NA> A
2: 3 A B
3: 4 B C
4: 5 C D
在列名中添加grep时该如何做？我正在尝试类似
> dt.x[!all(is.na(get(grep("question", names(dt.x), value = T))))]
row question_a question_b
1: 1 <NA> <NA>
2: 2 <NA> A …