相关疑难解决方法(0)

我有几个数据框,我想按行组合.在生成的单个数据框中,我想创建一个新变量,用于标识观察来自哪个数据集.

# original data frames
df1 <- data.frame(x = c(1, 3), y = c(2, 4))
df2 <- data.frame(x = c(5, 7), y = c(6, 8))

# desired, combined data frame
df3  <- data.frame(x = c(1, 3, 5, 7), y = c(2, 4, 6, 8),
                   source = c("df1", "df1", "df2", "df2")
# x y source
# 1 2    df1
# 3 4    df1
# 5 6    df2
# 7 8    df2

我怎样才能做到这一点？提前致谢!