add one column below another one in r

I have an issue in adding one column below another column.

i have a data like this :

and I want that column 2 be below 1:

do you have a suggestion?
thank you in advance

>Solution :

You could do

data.frame(Heading = c(df$`Heading 1`, df$`Heading 2`), value = rep(df$Value, 2))
#>   Heading value
#> 1      12     1
#> 2      99     0
#> 3      34     1
#> 4      42     0