R/dontrepeat.R

In cursory: A Cursory Look at Variables

#' Indicate that when printing repeat values should be hidden.
#'
#' @param x a vector
#' @param replace.with what to replace the value with.
#' @examples
#' library(dplyr)
#' library(tibble)
#' x <- cursory_all(group_by(iris, Species), lst(mean, sd))
#' x <- as.data.frame(arrange(x, Species))
#' print(x)
#' x[[1]] <- dontrepeat(x[[1]], replace.with='"')
#' print(x)
#' @export
dontrepeat <- function(x, replace.with='')
    structure( add_class(forcats::fct_inorder(x), 'dontrepeat')
             , replace.with=replace.with)

#' @export
format.dontrepeat <- function(x, ..., replace.with = attr(x, 'replace.with') %||% ''){
    repeats <- c(FALSE, head(x, -1) == tail(x, -1))
    ifelse(repeats, format(replace.with, ...), NextMethod())
}
if(FALSE){#@testing
    x <- dontrepeat(c('a','a', 'b', 'b', 'b'))
    val <- format(x)
    expect_identical(val, c('a', '', 'b', '', ''))

    x <- dontrepeat(c('a','a', 'b', 'b', 'b'), '.')
    val <- format(x)
    expect_identical(val, c('a', '.', 'b', '.', '.'))

    x <- dontrepeat(c('a','a', 'b', 'b', 'b'), '.')
    val <- format(x, replace.with='-')
    expect_identical(val, c('a', '-', 'b', '-', '-'))

    x <- dontrepeat(c('a','a', 'b', 'b', 'b'), '.')
    val <- format(x, replace.with='-', width=5, justify='right')
    expect_identical(val, c('    a', '    -', '    b', '    -', '    -'))
}

#' @export
`[.dontrepeat` <- function(x,...)carry_forward(NextMethod(), x)
#' @export
`c.dontrepeat` <- function(x,...)carry_forward(NextMethod(), x)
if(FALSE){
    x <- dontrepeat(c('a','a', 'b', 'b', 'b'), '.')
    val <- x[TRUE]

    expect_is(val, 'dontrepeat')
    expect_equal(attr(val, 'replace.with'), '.')
}

# This function is required to ensure that knitr::kable output
# is correct.
#' @export
as.vector.dontrepeat <- function(x, mode="any"){
    if (mode=="list") carry_forward(as.list(x), x) else
    if (mode == "any" || mode == "character")
        format(x)
    else NextMethod()
}

if(FALSE){#@testing dontrepeat in a tbl
    x <- tibble::tibble( x = dontrepeat(c('a','a', 'b', 'b', 'b'), '.')
                       , y = 1:5
                       )
    expect_is(x$x, 'dontrepeat')
    expect_is(head(x, 5)$x, 'dontrepeat')


    expect_equal( format(as.data.frame(x))$x
                , I(c('a', '.', 'b', '.', '.')))

    M <- as.matrix(x)
    expect_identical(M, cbind( x=c('a', '.', 'b', '.', '.')
                             , y=1:5))
}