如何使用 ggplot2在轴上只显示整数值

With scale_y_continuous() and argument breaks= you can set the breaking points for y axis to integers you want to display.

ggplot(data2, aes(x =factor(IR), y = value, fill = Legend, width=.15)) +
geom_bar(position='dodge', colour='black')+
scale_y_continuous(breaks=c(1,3,7,10))

如果您有 scales包，您可以使用 pretty_breaks()而不必手动指定中断。

q + geom_bar(position='dodge', colour='black') +
scale_y_continuous(breaks= pretty_breaks())

我用的是这个:

ggplot(data3, aes(x = factor(IR), y = value, fill = Legend, width = .15)) +
geom_col(position = 'dodge', colour = 'black') +
scale_y_continuous(breaks = function(x) unique(floor(pretty(seq(0, (max(x) + 1) * 1.1)))))

可以使用自定义标签。例如，此函数保证只生成整数分割符:

int_breaks <- function(x, n = 5) {
l <- pretty(x, n)
l[abs(l %% 1) < .Machine$double.eps ^ 0.5]
}

用作

+ scale_y_continuous(breaks = int_breaks)

它的工作原理是使用默认的中断，并且只保留那些为整数的中断。如果你的数据中断太少，增加 n，例如:

+ scale_y_continuous(breaks = function(x) int_breaks(x, n = 10))

这些解决方案对我不起作用，也没有解释解决方案。

scale_*_continuous函数的 breaks参数可以与一个自定义函数一起使用，该函数将限制作为输入，并将中断返回作为输出。默认情况下，对于连续数据(相对于数据范围) ，轴限制将在每一侧扩展5% 。由于此展开，轴限制可能不是整数值。

我寻找的解决方案是简单地将下限四舍五入到最接近的整数，将上限四舍五入到最接近的整数，然后在这些端点之间的整数值处有中断。因此，我使用了 break 函数:

brk <- function(x) seq(ceiling(x[1]), floor(x[2]), by = 1)

The required code snippet is:

scale_y_continuous(breaks = function(x) seq(ceiling(x[1]), floor(x[2]), by = 1))

原问题中可重复的例子是:

data3 <-
structure(
list(
IR = structure(
c(4L, 3L, 2L, 1L, 4L, 3L, 2L, 1L),
.Label = c("0.13-0.16", "0.17-0.23", "0.24-0.27", "0.28-1"),
class = "factor"
),
variable = structure(
c(1L, 1L, 1L, 1L,
2L, 2L, 2L, 2L),
.Label = c("Real queens", "Simulated individuals"),
class = "factor"
),
value = c(2L, 2L, 6L, 10L, 0L, 1L, 4L,
4L),
Legend = structure(
c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L),
.Label = c("Real queens",
"Simulated individuals"),
class = "factor"
)
),
row.names = c(NA,-8L),
class = "data.frame"
)


ggplot(data3, aes(
x = factor(IR),
y = value,
fill = Legend,
width = .15
)) +
geom_col(position = 'dodge', colour = 'black') + ylab('Frequency') + xlab('IR') +
scale_fill_grey() +
scale_y_continuous(
breaks = function(x) seq(ceiling(x[1]), floor(x[2]), by = 1),
expand = expand_scale(mult = c(0, 0.05))
) +
theme(axis.text.x=element_text(colour="black", angle = 45, hjust = 1),
axis.text.y=element_text(colour="Black"),
panel.grid.major = element_blank(),
panel.grid.minor = element_blank(),
panel.border = element_blank(),
panel.background = element_blank(),
axis.ticks.x = element_blank())

This answer builds on @Axeman's answer to address the comment by kory that if the data only goes from 0 to 1, no break is shown at 1. This seems to be because of inaccuracy in pretty with outputs which appear to be 1 not being identical to 1 (see example at the end).

因此，如果你使用

int_breaks_rounded <- function(x, n = 5)  pretty(x, n)[round(pretty(x, n),1) %% 1 == 0]

和

+ scale_y_continuous(breaks = int_breaks_rounded)

0和1都显示为休止符。

Example to illustrate difference from Axeman's

testdata <- data.frame(x = 1:5, y = c(0,1,0,1,1))


p1 <- ggplot(testdata, aes(x = x, y = y))+
geom_point()




p1 + scale_y_continuous(breaks = int_breaks)
p1 + scale_y_continuous(breaks =  int_breaks_rounded)

两者都将使用初始问题中提供的数据。

说明为什么需要四舍五入

pretty(c(0,1.05),5)
#> [1] 0.0 0.2 0.4 0.6 0.8 1.0 1.2
identical(pretty(c(0,1.05),5)[6],1)
#> [1] FALSE