r - 我怎样才能在除一列之外的所有列上收集_？

Question

我需要gather_数据帧的所有列(除了一列)。示例:

# I want to generate a dataframe whose column names are the letters of the alphabet. If you know of a simpler way, let me know!
foo <- as.data.frame(matrix(runif(100), 10, 10))
colnames(foo) <- letters[1:10]

现在，假设我想收集除 e 列之外的所有列。这是行不通的:

mycol <- "e"
foo_melt <- gather_(foo, key = "variable", value = "value", -mycol)
#Error in -mycol : invalid argument to unary operator

这将:

column_list <- colnames(foo)
column_list <- column_list[column_list != mycol]
foo_melt <- gather_(foo, key = "variable", value = "value", column_list)

如果你问我的话，我看起来很复杂。有没有更简单的方法？

Answer 1

一个选项是 one_of 和 gather

res1 <- gather(foo, key = "variable", value = "value", -one_of(mycol))

如果我们需要gather_，那么可以使用setdiff

res2 <- gather_(foo, key = "variable", value = "value", setdiff(names(foo), mycol))

identical(res1, res2)
#[1] TRUE
dim(res1)
#[1] 90  3

head(res1, 3)
#          e variable     value
#1 0.8484310        a 0.2730847
#2 0.0501665        a 0.8129584
#3 0.6689233        a 0.5457884