Question

我需要在数据框的所有列上gather_，除了一个。例如：

# 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，假设我想收集列e以外的所有列。这不起作用：

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，看起来很复杂。有没有更简单的方法？

Answer 1

一个选项是one_of gather

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

如果我们需要gather_，则可以使用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

Answer 2

试试这个：

foo_melt <- gather_(foo, key = "variable", value = "value",names(foo)[-5])

这将为您提供除第5列以外的所有列（＆＃34; e＆＃34;）。

> head(foo_melt)
          e variable     value
1 0.6359394        a 0.9567835
2 0.1558724        a 0.7778139
3 0.1418696        a 0.2132809
4 0.7184244        a 0.4539194
5 0.4487064        a 0.1049392
6 0.5963304        a 0.8692680

我怎样才能收集所有列而不是一列？

2 个答案: