R ggplot2 position_dodge 躲避左右重疊的物體

position_dodge(width = NULL, preserve = "total")

position_dodge2(
  width = NULL,
  preserve = "total",
  padding = 0.1,
  reverse = FALSE
)

其他位置調整：position_identity()、position_jitterdodge()、position_jitter()、position_nudge()、position_stack()

ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = "dodge2")


# By default, dodging with `position_dodge2()` preserves the total width of
# the elements. You can choose to preserve the width of each element with:
ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = position_dodge2(preserve = "single"))


# \donttest{
ggplot(diamonds, aes(price, fill = cut)) +
  geom_histogram(position="dodge2")
#> `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# see ?geom_bar for more examples

# In this case a frequency polygon is probably a better choice
ggplot(diamonds, aes(price, colour = cut)) +
  geom_freqpoly()
#> `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# }

# Dodging with various widths -------------------------------------
# To dodge items with different widths, you need to be explicit
df <- data.frame(
  x = c("a","a","b","b"),
  y = 2:5,
  g = rep(1:2, 2)
)
p <- ggplot(df, aes(x, y, group = g)) +
  geom_col(position = "dodge", fill = "grey50", colour = "black")
p


# A line range has no width:
p + geom_linerange(aes(ymin = y - 1, ymax = y + 1), position = "dodge")
#> Warning: Width not defined
#> ℹ Set with `position_dodge(width = ...)`


# So you must explicitly specify the width
p + geom_linerange(
  aes(ymin = y - 1, ymax = y + 1),
  position = position_dodge(width = 0.9)
)


# The same principle applies to error bars, which are usually
# narrower than the bars
p + geom_errorbar(
  aes(ymin = y - 1, ymax = y + 1),
  width = 0.2,
  position = "dodge"
)

p + geom_errorbar(
  aes(ymin = y - 1, ymax = y + 1),
  width = 0.2,
  position = position_dodge(width = 0.9)
)


# Box plots use position_dodge2 by default, and bars can use it too
ggplot(mpg, aes(factor(year), displ)) +
  geom_boxplot(aes(colour = hwy < 30))


ggplot(mpg, aes(factor(year), displ)) +
  geom_boxplot(aes(colour = hwy < 30), varwidth = TRUE)


ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = position_dodge2(preserve = "single"))


ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
  geom_bar(position = position_dodge2(preserve = "total"))