如何为geom_point大小添加条件?

时间:2010-03-02 07:43:38

标签: r size ggplot2 scale

我正在尝试为geom_point大小添加一个条件,我在下面粘贴了我的示例。当n_in_stat为4或更大时,我希望geom_point大小为2,当n_in_stat小于4时,我希望size = 5.我尝试在geom_point中放置一个ifelse语句,但是这个失败了。也许我不能在这里包含逻辑运算符,我必须在data.frame中创建一个新列并将其大小设置为?

geom_point(size = ifelse(n_in_stat< 4,5,2))+#尝试使用ifelse设置大小

geom_point(aes(size = n_in_stat))+#original原始缩放

library(ggplot2)

# Create a long data.frame to store data...
growth_series = data.frame ("read_day" = c(0, 3, 9, 0, 3, 9, 0, 2, 8), 
"series_id" = c("p1s1", "p1s1", "p1s1", "p1s2", "p1s2", "p1s2", "p3s4", "p3s4", "p3s4"),
"mean_od" = c(0.6, 0.9, 1.3, 0.3, 0.6, 1.0, 0.2, 0.5, 1.2),
"sd_od" = c(0.1, 0.2, 0.2, 0.1, 0.1, 0.3, 0.04, 0.1, 0.3),
"n_in_stat" = c(8, 8, 8, 8, 7, 5, 8, 7, 2)
)

# Plot using ggplot...
ggplot(data = growth_series, aes(x = read_day, y = mean_od, group = series_id, color = series_id)) +
geom_line(size = 1.5) +
geom_point(aes(size = n_in_stat)) +
geom_errorbar(aes(ymin = mean_od - sd_od, ymax = mean_od + sd_od), size = 1, width = 0.3) +
xlab("Days") + ylab("Log (O.D. 730 nm)") +
scale_y_log2() +
scale_colour_hue('my legend', breaks = levels(growth_series$series_id), labels=c('t1', 't2', 't3'))

2 个答案:

答案 0 :(得分:4)

scale_size_manual设置离散变量的大小。

geom_point(aes(size =n_in_stat>4)) + scale_size_manual(values=c(2,5))

答案 1 :(得分:2)

你也可以使用一个函数:

ff <- function(x){ifelse(x < 4, 5, 2)}

然后更改

geom_point(aes(size = n_in_stat)) +

geom_point(aes(size = ff(n_in_stat))) +