Marius - 6 months ago 26

R Question

I have a resulting data frame with only one column that contains lists of uneven lengths:

`data = list(`

c(349, 364, 393, 356, 357, 394, 334, 394, 343, 365, 349),

c(390, 336, 752, 377),

c(670, 757, 405, 343, 1109, 350, 372),

c(0, 0),

c(),

c(1115, 394, 327, 356, 408, 329, 385, 357, 357))

and i would like to convert it to a matrix, filling the gaps with

`NA`

So it should look something like this:

`349, 364, 393, 356, 357, 394, 334, 394, 343, 365, 349`

390, 336, 752, 377, NA, NA, NA, NA, NA, NA, NA

670, 757, 405, 343, 1109,350, 372, NA, NA, NA, NA

0, 0, NA, NA, NA, NA, NA, NA, NA, NA, NA

NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA

1115,394, 327, 356, 408, 329, 385, 357, 357, NA, NA

eventually even get rid of the rows with only

`NAs`

I have tried

`data = sapply(data[,1], FUN=unlist)`

`data = sapply(data, '[', seq(max(sapply(data, length))))`

Answer

I guess the 'data' should be a `list`

instead of a `vector`

, then the code would work

```
t(sapply(data, `length<-`, max(lengths(data))))
```

NOTE: `lengths`

is a faster option (introduced in the recent R versions) that replaces `sapply(data, length)`

```
data = list(
c(349, 364, 393, 356, 357, 394, 334, 394, 343, 365, 349),
c(390, 336, 752, 377),
c(670, 757, 405, 343, 1109, 350, 372),
c(0, 0),
numeric(0),
c(1115, 394, 327, 356, 408, 329, 385, 357, 357))
```