小编Jul*_*les的帖子

样本数据集:

library(ggplot2)    
df = read.table(text = 
              "id      year    value1  value2 value3
            1           2000    1   2000      2001
            1           2001    2   NA        NA
            1           2002    2   2000      NA
            1           2003    2   NA         2003
            2           2000    1   2001     2003
            2           2002    2   NA       2000
            2           2003    3   2002     NA
            3           2002    2   2001     NA
        ", sep = "", header = TRUE)
df$value1 <- as.factor(df$value1)

我知道如何改变三个级别的因子变量的颜色:

p <- ggplot(df, aes(y=id))
p <- p + scale_colour_manual(name="",  values =c("yellow", "orange", "red"))
p <- p + geom_point(aes(x=year, …