如何在ggplot中将表达式传递给geom_text标签? [英] How to pass an expression to a geom_text label in ggplot?
问题描述
我试图将带下标的表达式传递给ggplot
中的单个geom_text()
标签.这是我现在的代码:
I am attempting to pass an expression with subscript to a single geom_text()
label in ggplot
. Here is my code right now:
my_exp <- expression('my_exp'[s][u][b])
my_data <-
data.frame(
var_1 = c("a", "b", "c"),
var_2 = c(1, 2, 3)
)
my_data %>%
ggplot(aes(x = var_1, y = var_2))+
geom_text(aes(label = var_1))
这是结果图:
我想做的是用my_exp
指定的表达式替换"a"
的var_1
值,然后让geom_text()
将该值作为表达式求值,导致下标出现在ggplot上.
What I would like to do is replace the var_1
value of "a"
with the expression specified by my_exp
and then have geom_text()
evaluate that value as an expression, resulting in the subscript appearing on the ggplot.
推荐答案
我建议采用这种方法.您可以为标签构建另一个变量,然后启用geom_text()
中的选项parse=T
,以获得所需的图.这里的代码:
I would suggest this approach. You can build another variable for your labels and then enable the option parse=T
from geom_text()
in order to have the desired plot. Here the code:
library(ggplot2)
library(tidyverse)
#Data
my_exp <- as.character(expression('my_exp'[s][u][b]))
my_data <-
data.frame(
var_1 = c("a", "b", "c"),
var_2 = c(1, 2, 3),stringsAsFactors = F
)
#Mutate
my_data$label <- ifelse(my_data$var_1=='a',my_exp,my_data$var_1)
#Plot
my_data %>%
ggplot(aes(x = var_1, y = var_2))+
geom_text(aes(label = label),parse = T)
输出:
更新:如果此处的标签有问题,请使用相应的代码
Update: If there are issues with labels here a code for that:
#Label
my_exp <- "14~M~my_exp[s][u][b]"
#Code
my_data <-
data.frame(
var_1 = c("a", "b", "c"),
var_2 = c(1, 2, 3),stringsAsFactors = F
)
#Mutate
my_data$label <- ifelse(my_data$var_1=='a',my_exp,my_data$var_1)
#Plot
my_data %>%
ggplot(aes(x = var_1, y = var_2))+
geom_text(aes(label = label),parse = T)
输出:
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