unlist and split a column without losing information of other column in R

I have a column with special character ";" that I want to separate into new rows without loosing information of other columns.

let’s say, this is my df:

col1  year
A;B    2010
A      2010
B      2011
B;C    2012

the desired result:

col1  year
A      2010
B      2010
A      2010
B      2011
B      2012
C      2012

I know how to seperate col1 using strsplit :

unlist(strsplit(df[,1], ";")

but this does not keep the information of other columns.

>Solution :

We can use separate_rows

library(tidyr)
separate_rows(df, col1, sep = ";")

If we want to use strsplit, then have to replicate the rows based on the length of list elements (lengths)

lst1 <- strsplit(df$col1, ";")
df1 <- df[rep(seq_len(nrow(df)), lengths(lst1)),]
df1$col1 <- unlist(lst1)