Importing CSV of arrays as list - r

Question

I'm trying to do the following:
I have a .csv file with N rows and 2 columns that I need to import and convert to a list.
Example file from .csv:
First seven rows of data
I import with command: points <- read.csv("points.csv")
'data.frame': 42 obs. of 2 variables:
$ Firefly : int 0 1 0 1 0 1 0 1 0 1 ...
$ Hawkes_times: Factor w/ 42 levels "[ 0.03485687 0.20167375 0.20275073
I need it as a sorted "List of 2" (one for each Firefly) with the following structure:
> str(points)
List of 2
$ : num [1:33] 0.79 0.87 0.88 0.89 0.94 1.01 1.13 1.19 ...
$ : num [1:14] 0.00 0.10 0.56 0.67 1.27 1.31 1.37 1.42 ...
, where the first list represents Firefly == 0 and second list represents Firefly == 1.
I attempt the following:
fy0 <- subset(points,Firefly == 0)
fy1 <- subset(points,Firefly == 1)
points.list <- list(fy0,fy1)
> str(points.list)
List of 2
$ :'data.frame': 21 obs. of 2 variables:
..$ Firefly : int [1:21] 0 0 0 0 0 0 0 0 0 0 ...
..$ Hawkes_times: Factor w/ 42 levels "[ 0.03485687 0.20167375 0.20275073 0.20941455 0.40515277 0.47026309\n 0.55714817 0.64789982 0.70749241 "| __truncated__,..: 30 29 28 31 39 40 33 37 25 24 ...
$ :'data.frame': 21 obs. of 2 variables:
..$ Firefly : int [1:21] 1 1 1 1 1 1 1 1 1 1 ...
..$ Hawkes_times: Factor w/ 42 levels "[ 0.03485687 0.20167375 0.20275073 0.20941455 0.40515277 0.47026309\n 0.55714817 0.64789982 0.70749241 "| __truncated__,..: 26 32 21 23 20 41 34 22 27 36 ...
I think I need a as.numeric(fy0$Hawkes_times) somewhere, but I want to avoid loops since I will have hundreds of rows and n Firefly values (fy0, fy1, fy2, ... fyn).
Thank you!
-Richard

Answer 1

points <- data.frame(firefly=rep(0:1, times=10), times=1:20)
split(points$times, points$firefly)
# $`0`
# [1] 1 3 5 7 9 11 13 15 17 19
# $`1`
# [1] 2 4 6 8 10 12 14 16 18 20
This does not rely on equally-sized groups:
set.seed(42)
points <- data.frame(firefly=sample(0:1, size=20, replace=TRUE), times=1:20)
split(points$times, points$firefly)
# $`0`
# [1] 3 8 11 14 15 18 19
# $`1`
# [1] 1 2 4 5 6 7 9 10 12 13 16 17 20
and as you can see the order is preserved.