Convert dataframe to list with numeric vectors in r

Question

I would like to transform values from a dataset to a list as numeric values.

Here is a sample dataset:

df <- data.frame(
  a = c(5.5, 6, 7),
  b = c(1.1, 2.5, 3.5))

# convert dataframe to list
df.list <- split(df, seq(nrow(df)))

The list looks like the above in the R environment. My desired output in the R environment is like below by getting rid of the $s, as, and bs.

I tried this below but it did not really give what I wanted.

for (i in 1:length(df.list)) {
  df.list[[i]] <- lapply(df.list[[i]], function(x) as.numeric(as.character(df.list[[i]])))
  
}

Does ANyone have any ideas?

Thanks!

akrun · Accepted Answer · 2021-05-05 19:42:46Z

1

We can use asplit from base R. Specify the MARGIN as 1 for rows and 2 for column wise split

out <- lapply(asplit(unname(df), 1), as.vector)
str(out)
#List of 3
#$ : num [1:2] 5.5 1.1
#$ : num [1:2] 6 2.5
#$ : num [1:2] 7 3.5

Or another option is apply

out2 <- do.call(c, apply(unname(df), 1, list)) 
identical(out, out2)
#[1] TRUE

From the OP's split, we can unlist the list elements

out3 <- lapply(unname(df.list), unlist, use.names = FALSE)
identical(out, out3)
#[1] TRUE

answered May 5, 2021 at 19:37

akrun

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1 Comment

appreciated your quick turnaround. Great solutions. I picked the first one.