flatten a data frame

Question

I have this nested data frame

test <- structure(list(id = c(13, 27), seq = structure(list(
`1` = c(\"1997\", \"1997\", \"1997\", \"2007\"),
`2` = c(\"2007\",         


        

Answer 1

This line does the trick:

do.call("c", test[["seq"]])

or equivalent:

c(test[["seq"]], recursive = TRUE)

or even:

unlist(test[["seq"]])

The output of these functions is:

    11     12     13     14     21     22     23     24     25     26     27 
"1997" "1997" "1997" "2007" "2007" "2007" "2007" "2007" "2007" "2007" "2007" 

To get rid of the names above the character vector, call as.character on the resulting object:

> as.character((unlist(test[["seq"]])))
 [1] "1997" "1997" "1997" "2007" "2007" "2007" "2007" "2007" "2007" "2007"
[11] "2007"