Create a “cj_df” data frame

A simple data frame extension that preserves attributes during subsetting operations.

cj_df(x)

# S3 method for data.frame
cj_df(x)

# S3 method for cj_df
[(x, i, j, drop = FALSE)

Arguments

x	A data frame
i	See [.data.frame
j	See [.data.frame
drop	Ignored.

Value

An data frame with additional “cj_df” class, which has subsetting methods that preserve variables attributes.

Examples

x1 <- data.frame(a = 1:3, b = 4:6)
attr(x1$a, "label") <- "Variable A"

# cj_df() returns a data frame
inherits(x1, "data.frame")
#> [1] TRUE
class(x1)
#> [1] "data.frame"

# attributes dropped for data frames
attr(x1[1:2,]$a, "label")
#> NULL

# attributes preserved with a cj_df
attr(cj_df(x1)[1:2,]$a, "label")
#> [1] "Variable A"