Converting a data.frame to a list of lists
LMAo <- lapply(split(df,df$id), function(x) as.list(x)) # is one way
# more succinctly
# LMAo <- lapply(split(df,df$id), as.list)
An edited solution as per your comment:
lapply( split(df,seq_along(df[,1])), as.list)
In base R, it's quite a bit faster to use mapply
instead of split
or lapply
- however, you have to invoke it via do.call
so that each column is used independently.
df <- sleep
f <- function(df) {
lapply(seq_len(nrow(df)), function(row) {
df[row, , drop = FALSE]
})
}
f2 <- function(df) {
do.call("mapply", c(list, df, SIMPLIFY = FALSE, USE.NAMES=FALSE))
}
f3 <- function(df) {
split(df, seq(nrow(df)))
}
microbenchmark::microbenchmark(f(df), f2(df), f3(df))
#> Unit: microseconds
#> expr min lq mean median uq max neval
#> f(df) 573.799 607.8375 759.1721 626.0095 752.9465 2861.961 100
#> f2(df) 114.819 123.5190 155.5185 129.9210 141.4340 1375.573 100
#> f3(df) 598.774 625.6025 813.6837 634.5855 684.3825 11230.678 100
Created on 2019-10-09 by the reprex package (v0.3.0)
You can use apply
to turn your data frame into a list of lists like this:
LoL <- apply(df,1,as.list)
However, this will change all your data to text, as it passes a single atomic vector to the function.
Using plyr
, you can do this
dlply(df,.(id),c)
To avoid grouping by id , if there are multiple ( maybe you need to change column name , id is unique for me)
dlply(df,1,c)