R/GGPlot2Tools_Segments2Points.R

In Ilia-Kosenkov/RLibs: RLibs

#   MIT License
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#   Copyright(c) 2017-2018 Ilia Kosenkov [ilia.kosenkov.at.gm@gmail.com]
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utils::globalVariables(c("Key__", "Val__", "ID__"))
#' @title Segments2Points
#' @param .dt Input table.
#' @param x \code{x} column name.
#' @param y \code{y} column name.
#' @param xend \code{x} end column name.
#' @param yend \code{y} end column name.
#' @return Trnasformed table.
#' @importFrom rlang enquo quo_squash !!
#' @importFrom dplyr %>% mutate select slice row_number if_else n
#' @importFrom tidyr gather spread
#' @export
Segments2Points <- function(.dt, x, y, xend, yend) {
    nx <- quo_squash(enquo(x))
    ny <- quo_squash(enquo(y))
    nx2 <- quo_squash(enquo(xend))
    ny2 <- quo_squash(enquo(yend))

    .dt %>%
        gather(Key__, Val__, !!nx, !!nx2, !!ny, !!ny2) %>%
        mutate(Key__ = if_else(row_number() <= (n() / 2), a_ch(nx), a_ch(ny)),
               ID__ = rep(1:(n() / 2), 2)) %>%
        spread(Key__, Val__) %>%
        select(-ID__) %>%
        slice(UniqueWhichTol(!!nx))
}