Use of scale_x_discrete in R ggplot2

Question

I have a problem using the discrete scale in ggplot2 in R. The use of

g + scale_x_discrete(breaks=1:7, labels=1:7)

incorrectly changes in limits of a plot.

Before:

After:

I cannot see anything suspicious about the code I use to produce the image, but here is it:

g <- ggplot(data=plottingData, aes(x=x, y=y, ymin=ymin, ymax=ymax)) +
geom_bar(stat="identity", fill=col) +
geom_errorbar(width=0.5*binwidth, size=0.3)

And here is the dput() of the resulting ggplot2 object:

structure(list(data = structure(list(x = c(1, 2, 3, 4, 5, 6,  7), y = c(0.689655172413793, 0.689655172413793, 11.0344827586207,  2.75862068965517, 70.3448275862069, 13.7931034482759, 0.689655172413793 ), ymin = c(0, 0, 6.84765916431683, 0.870298113507349, 62.426550974053,  9.06894448064895, 0), ymax = c(4.26873021234759, 4.26873021234759,  17.3134146611865, 7.18339316166044, 77.1707644621886, 20.4612568616329,  4.26873021234759)), .Names = c("x", "y", "ymin", "ymax"), row.names = c(NA,  -7L), class = "data.frame"), layers = list(<environment>, <environment>),      scales = <S4 object of class structure("Scales", package = "ggplot2")>,      mapping = structure(list(x = x, y = y, ymin = ymin, ymax = ymax), .Names = c("x",      "y", "ymin", "ymax"), class = "uneval"), theme = structure(list(         line = structure(list(colour = "black", size = 0.5, linetype = 1,              lineend = "butt"), .Names = c("colour", "size", "linetype",          "lineend"), class = c("element_line", "element")), rect = structure(list(             fill = "white", colour = "black", size = 0.5, linetype = 1), .Names = c("fill",          "colour", "size", "linetype"), class = c("element_rect",          "element")), text = structure(list(family = "", face = "plain",              colour = "black", size = 12, hjust = 0.5, vjust = 0.5,              angle = 0, lineheight = 0.9), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          axis.text = structure(list(family = NULL, face = NULL,              colour = NULL, size = structure(0.8, class = "rel"),              hjust = NULL, vjust = NULL, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          strip.text = structure(list(family = NULL, face = NULL,              colour = NULL, size = structure(0.8, class = "rel"),              hjust = NULL, vjust = NULL, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          axis.line = structure(list(), class = c("element_blank",          "element")), axis.text.x = structure(list(family = NULL,              face = NULL, colour = NULL, size = NULL, hjust = NULL,              vjust = 1, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          axis.text.y = structure(list(family = NULL, face = NULL,              colour = NULL, size = NULL, hjust = 1, vjust = NULL,              angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          axis.ticks = structure(list(colour = "black", size = NULL,              linetype = NULL, lineend = NULL), .Names = c("colour",          "size", "linetype", "lineend"), class = c("element_line",          "element")), axis.title.x = structure(list(family = NULL,              face = NULL, colour = NULL, size = NULL, hjust = NULL,              vjust = NULL, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          axis.title.y = structure(list(family = NULL, face = NULL,              colour = NULL, size = NULL, hjust = NULL, vjust = NULL,              angle = 90, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          axis.ticks.length = structure(0.15, unit = "cm", valid.unit = 1L, class = "unit"),          axis.ticks.margin = structure(0.1, unit = "cm", valid.unit = 1L, class = "unit"),          legend.background = structure(list(fill = NULL, colour = NA,              size = NULL, linetype = NULL), .Names = c("fill",          "colour", "size", "linetype"), class = c("element_rect",          "element")), legend.margin = structure(0.2, unit = "cm", valid.unit = 1L, class = "unit"),          legend.key = structure(list(fill = NULL, colour = "grey80",              size = NULL, linetype = NULL), .Names = c("fill",          "colour", "size", "linetype"), class = c("element_rect",          "element")), legend.key.size = structure(1.2, unit = "lines", valid.unit = 3L, class = "unit"),          legend.key.height = NULL, legend.key.width = NULL, legend.text = structure(list(             family = NULL, face = NULL, colour = NULL, size = structure(0.8, class = "rel"),              hjust = NULL, vjust = NULL, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          legend.text.align = NULL, legend.title = structure(list(             family = NULL, face = "bold", colour = NULL, size = structure(0.8, class = "rel"),              hjust = 0, vjust = NULL, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          legend.title.align = NULL, legend.position = "right",          legend.direction = NULL, legend.justification = "center",          legend.box = NULL, panel.background = structure(list(             fill = "white", colour = NA, size = NULL, linetype = NULL), .Names = c("fill",          "colour", "size", "linetype"), class = c("element_rect",          "element")), panel.border = structure(list(fill = NA,              colour = "grey50", size = NULL, linetype = NULL), .Names = c("fill",          "colour", "size", "linetype"), class = c("element_rect",          "element")), panel.grid.major = structure(list(colour = "grey90",              size = 0.2, linetype = NULL, lineend = NULL), .Names = c("colour",          "size", "linetype", "lineend"), class = c("element_line",          "element")), panel.grid.minor = structure(list(colour = "grey98",              size = 0.5, linetype = NULL, lineend = NULL), .Names = c("colour",          "size", "linetype", "lineend"), class = c("element_line",          "element")), panel.margin = structure(0.25, unit = "lines", valid.unit = 3L, class = "unit"),          panel.margin.x = NULL, panel.margin.y = NULL, strip.background = structure(list(             fill = "grey80", colour = "grey50", size = 0.2, linetype = NULL), .Names = c("fill",          "colour", "size", "linetype"), class = c("element_rect",          "element")), strip.text.x = structure(list(family = NULL,              face = NULL, colour = NULL, size = NULL, hjust = NULL,              vjust = NULL, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          strip.text.y = structure(list(family = NULL, face = NULL,              colour = NULL, size = NULL, hjust = NULL, vjust = NULL,              angle = -90, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          plot.background = structure(list(fill = NULL, colour = "white",              size = NULL, linetype = NULL), .Names = c("fill",          "colour", "size", "linetype"), class = c("element_rect",          "element")), plot.title = structure(list(family = NULL,              face = NULL, colour = NULL, size = structure(1.2, class = "rel"),              hjust = NULL, vjust = NULL, angle = NULL, lineheight = NULL), .Names = c("family",          "face", "colour", "size", "hjust", "vjust", "angle",          "lineheight"), class = c("element_text", "element")),          plot.margin = structure(c(1, 1, 0.5, 0.5), unit = "lines", valid.unit = 3L, class = "unit")), .Names = c("line",      "rect", "text", "axis.text", "strip.text", "axis.line", "axis.text.x",      "axis.text.y", "axis.ticks", "axis.title.x", "axis.title.y",      "axis.ticks.length", "axis.ticks.margin", "legend.background",      "legend.margin", "legend.key", "legend.key.size", "legend.key.height",      "legend.key.width", "legend.text", "legend.text.align", "legend.title",      "legend.title.align", "legend.position", "legend.direction",      "legend.justification", "legend.box", "panel.background",      "panel.border", "panel.grid.major", "panel.grid.minor", "panel.margin",      "panel.margin.x", "panel.margin.y", "strip.background", "strip.text.x",      "strip.text.y", "plot.background", "plot.title", "plot.margin"     ), class = c("theme", "gg"), complete = TRUE), coordinates = structure(list(         limits = structure(list(x = NULL, y = NULL), .Names = c("x",          "y"))), .Names = "limits", class = c("cartesian", "coord"     )), facet = structure(list(shrink = TRUE), .Names = "shrink", class = c("null",      "facet")), plot_env = <environment>, labels = structure(list(         x = "x", y = "y", ymin = "ymin", ymax = "ymax"), .Names = c("x",      "y", "ymin", "ymax"))), .Names = c("data", "layers", "scales",  "mapping", "theme", "coordinates", "facet", "plot_env", "labels" ), class = c("gg", "ggplot"))

Notably, the expand parameter only adjusts the plots slightly and expand=c(0,0) does not solve the problem. Specifying limits does solve the problem, but also removes the axis labels for some reason.

Any help would be appreciated.

Answer 1

p1 + scale_x_continuous(breaks = c(2, 4, 6))

Answer 2

That probably already happens when you add g + scale_x_discrete(). This happens when using a discrete scale for continuous data. Without the breaks, you can see the wrong limits and just change them.

g + scale_x_discrete()
g + scale_x_discrete(limits=1:7)
g + scale_x_discrete(limits=1:7, labels = letters[1:7])

Alternatively, you can use factor to get the proper limits from the beginning. Of course you'll have to rename the axis.

ggplot(data=plottingData, aes(x=factor(x), y=y, ymin=ymin, ymax=ymax)) +
  geom_bar(stat="identity", fill=col) +
  geom_errorbar(width=0.5*binwidth, size=0.3) +
  scale_x_discrete(name = 'x')