In a data frame, I am attempting to duplicate the first occurence of a string into the same column, but also into the neighbouring column. More specifically, I want the first occurence of a string in column v1 to be duplicated and inserted above itself and above the same row in column v2, as exemplified in the mock data frame below:

Input:

```
df_1<-data.frame("v1"=c(rep("a",times=3),rep("aa",times=4)),"v2"=c(c("b","c","d"),c("bb","cc","dd","ee")))
df_1
      v1 v2
    1  a  b
    2  a  c
    3  a  d
    4 aa bb
    5 aa cc
    6 aa dd
    7 aa ee

```

Expected output:

```
df_2<-data.frame("v1"=c(rep("a",times=4),rep("aa",times=5)),"v2"=c(c("a","b","c","d"),c("aa","bb","cc","dd","ee")))
df_2
    v1 v2
    1  a  a
    2  a  b
    3  a  c
    4  a  d
    5 aa aa
    6 aa bb
    7 aa cc
    8 aa dd
    9 aa ee

```

So in this case, the first occurence of "a" and "aa" has been duplicated and inserted into the same data frame above it's first occurence.

I hope my question makes sense.

Best,
Rikki