在R(ggplot)中注释公式(使用bqoute或替代项)会产生错误 [英] annotate a formula (with bqoute or substitute) in R (ggplot) gives Error
问题描述
我想在其中添加一个带有变量的公式作为对ggplot的注释.
I want to add a formula with variables in it as a annotation onto my ggplot.
regline1 <- 0.00
slope1 <- 1.00
dat <- as.data.frame(c(0,1))
dat[2] <- c(0,1)
names(dat) <- c("foo","bar")
p <-
ggplot(dat, aes(foo, bar)) + coord_fixed(ratio = 1) + geom_point() +
geom_abline(slope = slope1, intercept = intercept1, linetype = "dashed") +
labs(x = substitute(y[H1]==i+s%*%x,list(i=format(intercept1, digits = 1), s= format(slope1, digits = 1))))
如您所见,ggplot为labs(x = ...)计算公式是没有问题的,但是,如果您尝试添加批注:
As you can see it is no problem for ggplot to evaluate the formula for labs(x =...), but if you try to add an annotation:
p + annotate("text",x=0.75, y = 0.25, label = substitute(y[H1]==i+s%*%x,list(i=format(intercept1, digits = 1), s= format(slope1, digits = 1))))
它会给您一个错误:
Error: Aesthetics must be either length 1 or the same as the data (1): label
我可以这样解析annotate()中的粘贴调用:
I can parse a paste-call in annotate() like this:
p <- annotate("text",x= 0.75, y =0.25, label = "paste(y[H1]== intercept1+ slope1 %.%x)", parse = TRUE)
但是,由于它用引号引起来,因此不会写入变量值.不会完全解析引号中的replace()表达式.
However, this does not write the variable values, since its in quotation marks. The substitute()-expression in quotation marks will not be parsed at all.
那我该怎么办呢?
感谢您的帮助, 提前致谢 朱利叶斯
Any help is appreciated, thanks in advance Julius
推荐答案
annotate()函数不支持表达式.您需要传递一个字符串并设置parse=T
.
The annotate() function does not support expressions. you need to pass in a string and set parse=T
.
如果您首先构建表达式
myexpr <- substitute( y[H1]==i+s%*%x, list(
i = format(intercept1, digits = 1),
s= format(slope1, digits = 1))
)
您可以deparse()
它,并让annotate()
为您重新解析
You can deparse()
it and have annotate()
re-parse it for you
ggplot(dat, aes(foo, bar)) +
geom_point() +
geom_abline(slope = slope1, intercept = intercept1, linetype = "dashed") +
coord_fixed(ratio = 1) +
labs(x = myexpr) +
annotate("text",x=0.75, y = 0.25, label = deparse(myexpr), parse=TRUE)
这将导致
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