user-guide-2.R
In gginnards: Explore the Innards of 'ggplot2' Objects

## ---- include=FALSE, echo=FALSE-----------------------------------------------
library(knitr)
opts_chunk$set(fig.align = 'center', 
               fig.show = 'hold', fig.width = 7, fig.height = 4)
options(warnPartialMatchArgs = FALSE)

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library(ggplot2)
library(gginnards)
library(tibble)
library(magrittr)
library(stringr)
eval_pryr <- requireNamespace("pryr", quietly = TRUE)

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set.seed(4321)
# generate artificial data
my.data <- data.frame(
  group = factor(rep(letters[1:4], each = 30)),
  panel = factor(rep(LETTERS[1:2], each = 60)),
  y = rnorm(40),
  unused = "garbage"
)

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attr(my.data, "my.atr.char") <- "my.atr.value"
attr(my.data, "my.atr.num") <- 12345678

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old_theme <- theme_set(theme_bw())

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p <- ggplot(my.data, aes(group, y)) + 
  geom_point() +
  stat_summary(fun.data = mean_se, colour = "cornflowerblue", size = 1) +
  facet_wrap(~panel, scales = "free_x", labeller = label_both) +
  expand_limits(y = c(-2, 2))
p

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summary(p)

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names(p$layers)

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summary(p$layers)

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print(p$layers)

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str(p$layers[[1]])

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which_layers(p, "GeomPoint")
which_layers(p, "StatIdentity")
which_layers(p, "GeomPointrange")
which_layers(p, "StatSummary")
which_layers(p, idx = 1L)

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extract_layers(p, "GeomPoint")

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delete_layers(p, "GeomPoint")

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delete_layers(p, idx = 1L)

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delete_layers(p, "StatSummary")

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move_layers(p, "GeomPoint", position = "top")

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shift_layers(p, "GeomPoint", shift = +1)

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append_layers(p, geom_line(colour = "orange", size = 1), position = "bottom")


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append_layers(p, object = geom_line(colour = "orange", size = 1), 
              position = which_layers(p, "GeomPoint"))

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p1 <- p + 
  annotate("text", label = "text label", x = 1.1, y = 0, hjust = 0)
p1

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delete_layers(p1, "GeomText")

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num_layers(p)
num_layers(p %+% geom_point(colour = "blue"))
num_layers(p + geom_point(colour = "blue"))

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p1 <- p + theme_bw()
p1
p1 + theme_void()
p1 %+% theme_void()

## ----eval=FALSE---------------------------------------------------------------
#  summary(theme_bw())

## ---- eval=FALSE--------------------------------------------------------------
#  names(theme_bw())

## ---- eval=FALSE--------------------------------------------------------------
#  str(theme_bw()$text)

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mapped.vars <- 
  gsub("[~*\\%^]", " ", as.character(p$mapping)) %>%
  str_split(boundary("word")) %>%
  unlist() %>%
  c(names(p$facet$params$facets))

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data.vars <- names(p$data)

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unused.vars <- setdiff(data.vars, c(mapped.vars))
keep.idxs <- which(!data.vars %in% unused.vars)

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p1 <- p
p1$data <- p$data[ , keep.idxs]

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object.size(my.data)
object.size(p)
object.size(p1)

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names(my.data)
names(p$data)
names(p1$data)

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p1

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drop_vars(p)

## ---- eval = eval_pryr--------------------------------------------------------
pryr::address(my.data)
z <- p$data
pryr::address(z)

## ---- eval = eval_pryr--------------------------------------------------------
attr(my.data, "my.atr.num") <- 1324567
pryr::address(z)
pryr::address(my.data)

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data_attributes(p)

## -----------------------------------------------------------------------------
p + geom_debug(summary.fun = attributes)