Hi @eyavuz21,
What you're suggesting is possible, but unless there is a compelling reason not to load the whole data into R and then process it there, it's not a particularly efficient process.
Using the gapminder data as example (lets pretend country name is similar to your Participant column. We can load the whole data set into R, then split the data into separate data frames based on country, and then turn them all into matrices.
library(gapminder)
library(magrittr)
gapminder
#> # A tibble: 1,704 x 6
#> country continent year lifeExp pop gdpPercap
#> <fct> <fct> <int> <dbl> <int> <dbl>
#> 1 Afghanistan Asia 1952 28.8 8425333 779.
#> 2 Afghanistan Asia 1957 30.3 9240934 821.
#> 3 Afghanistan Asia 1962 32.0 10267083 853.
#> 4 Afghanistan Asia 1967 34.0 11537966 836.
#> 5 Afghanistan Asia 1972 36.1 13079460 740.
#> 6 Afghanistan Asia 1977 38.4 14880372 786.
#> 7 Afghanistan Asia 1982 39.9 12881816 978.
#> 8 Afghanistan Asia 1987 40.8 13867957 852.
#> 9 Afghanistan Asia 1992 41.7 16317921 649.
#> 10 Afghanistan Asia 1997 41.8 22227415 635.
#> # … with 1,694 more rows
country_matrix <-
gapminder %>%
split(gapminder$country) %>%
lapply(as.matrix)
# We can access a specific country by name or number
country_matrix[["Canada"]]
#> country continent year lifeExp pop gdpPercap
#> [1,] "Canada" "Americas" "1952" "68.750" "14785584" "11367.16"
#> [2,] "Canada" "Americas" "1957" "69.960" "17010154" "12489.95"
#> [3,] "Canada" "Americas" "1962" "71.300" "18985849" "13462.49"
#> [4,] "Canada" "Americas" "1967" "72.130" "20819767" "16076.59"
#> [5,] "Canada" "Americas" "1972" "72.880" "22284500" "18970.57"
#> [6,] "Canada" "Americas" "1977" "74.210" "23796400" "22090.88"
#> [7,] "Canada" "Americas" "1982" "75.760" "25201900" "22898.79"
#> [8,] "Canada" "Americas" "1987" "76.860" "26549700" "26626.52"
#> [9,] "Canada" "Americas" "1992" "77.950" "28523502" "26342.88"
#> [10,] "Canada" "Americas" "1997" "78.610" "30305843" "28954.93"
#> [11,] "Canada" "Americas" "2002" "79.770" "31902268" "33328.97"
#> [12,] "Canada" "Americas" "2007" "80.653" "33390141" "36319.24"