Here's an example of converting data from wide to long using the data.table package in R. In data.table, the function we will use is called "melt"
# Load the data.table library
library(data.table)
# Create a wide format dataset
wide_df <- data.table(
id = c(1, 2, 3),
x1 = c(10, 20, 30),
x2 = c(40, 50, 60),
x3 = c(70, 80, 90)
)
# Convert to long format using data.table's melt function
long_df <- melt(wide_df, id.vars = "id", variable.name = "variable", value.name = "value")
# Show the long format dataset
print(long_df)
id variable value
1: 1 x1 10
2: 2 x1 20
3: 3 x1 30
4: 1 x2 40
5: 2 x2 50
6: 3 x2 60
7: 1 x3 70
8: 2 x3 80
9: 3 x3 90