您可以尝试 stack

> setNames(stack(df),c("new","colName"))
  new colName
1   1      X1
2   1      X1
3   1      X1
4   3      X2
5   0      X2
6   1      X2
7   4      X3
8   0      X3
9   0      X3

数据

> dput(df)
structure(list(X1 = c(1L, 1L, 1L), X2 = c(3L, 0L, 1L), X3 = c(4L, 
0L, 0L)), class = "data.frame", row.names = c(NA, -3L))