I applied a function to a data frame like this

```
> head(df,16)
   ID    Area time
1   1 182.685    1
2   2 182.714    1
3   3 182.275    1
4   4 211.928    1
5   5 218.804    1
6   6 183.445    1
7   7 209.161    1
8   8 205.231    1
9   1 189.743    2
10  2 190.164    2
11  3 189.310    2
12  4 222.414    2
13  5 229.056    2
14  6 191.121    2
15  7 219.344    2
16  8 214.662    2
> autocorr1 <- aggregate(x=df$Area,by=list(df$ID), FUN=acf.fft)

```

..and I got this data frame:

```
  Group.1 x
1       1 c(1, 0.925757424630699, 0.858465741115086, 0.7..

```

I would like to convert it to such a data frame:

```
Group.1 x1                x2                 x3   
1     1  1 0.925757424630699  0.858465741115086  0.7..

```

I tried `as.data.frame(unlist())` and `lapply`, but both give me a concatenated single column data frame:

```
test1 <- do.call(rbind, lapply(autocorr1$x, data.frame, stringsAsFactors=FALSE))
test2 <- as.data.frame(unlist(autocorr1$x))

```