如何在 geom_text 粘贴命令中使用 `parse = T` 和类似 round 的函数？

问题描述

我想将多个线性模型的结果作为 geom_text 添加到我的图中，它们与散点图数据存储在相同的 tibble 中。由于我想使用近似符号 (%~~%) 并且在 geom_text 命令中设置了 r^2 作为上标 (parse=T) 的 r 平方。但是，它给了我：

Error in parse(text = text[[i]]) : <text>:1:14: unexpected symbol
1: r^2 %~~%0.25 RMSE

带有指向 M 中的 RMSE 的箭头。如果我省略 parse=T，它将绘图，但没有格式。此外，如果我通过简单地单击绘图命令结构并按 Ctrl+Enter 在 Rstudio 中运行它，它会给我：

Error: Cannot add ggproto objects together. Did you forget to add this object to a ggplot object?

如果我标记代码部分并点击 Ctrl+Enter，我会抛出意外的符号错误。有谁知道为什么以及如何规避这种情况？我已经尝试省略 RMSE 字符串部分，然后它只是在字符串的另一个位置抛出错误。它似乎与 round 命令有关，但我现在不知道如何规避它。这是整个绘图命令：

df %>% 
  ggplot(aes(x = value_height,y = rpm,col = variant )) +
  geom_smooth(method = 'lm',col = 'black',se = F) +
  # geom_smooth(method = 'lm',se = F) +
  geom_point(shape = 1) +
  geom_text(
    aes(label = paste0(
      'r^2 %~~%',round(R2_height,2),' RMSE %~~% ',round(RMSE_height,'\n y =',round(intercept_height,'+',round(slope_height,2 ),'x')),size = 4,x = 0.3,y = 10,parse = T) +
  facet_wrap(~date_rpm) +
  theme_bw() +
  theme(legend.position = c(.8,.2),legend.direction = 'horizontal') +
  scale_color_discrete(name='') +
  ylab('Rising Plate Meter (RPM)') +
  xlab('Crop Surface Height (CSH) [cm]') + 
  guides(colour = guide_legend(nrow = 3))

这是格式化字符串的外观，但我希望等号为近似符号，而 r2 为上标。

数据：

    df <- structure(list(date_rpm = structure(c(18416,18416,18416),class = "Date"),rpm = c(5,3.5,3,6,9,5,4,13,21,10,7.5,12,16,18,7,11,15,14,8,4.5,20,5.5,8.5,17,22,19.5,9.5,19,15),plotname = c("A1","A1","A2","A3","B3","B1","C1","C3","C2","B2","C2"),variant = c("Moderate","Moderate","Lenient","Very Lenient","Lenient"),diff = structure(c(2,2,class = "difftime",units = "days"),value_height = c(0.0747471996861645,0.0519722114175053,0.0444986718332666,0.0338748996540651,0.130905933869191,0.0627344897669605,0.0461518377320379,0.0496649014747749,0.0346351036658654,0.197689089000735,0.228481029642039,0.0869697505592281,0.247327755659054,0.110378037151108,0.190863379116716,0.153554587528623,0.214562251650054,0.173082661424947,0.309699486041891,0.117518367930355,0.0411031690694518,0.167414698107489,0.367566883054554,0.0802824884398371,0.157873638605667,0.189377089678231,0.125737899389022,0.158878721039871,0.241583593960466,0.238216268605199,0.352655443094544,0.121164650752627,0.119100065312834,0.087414577089507,0.279764767350822,0.116740391172212,0.146888537284655,0.0964947561932425,0.116610769498146,0.0829571222854873,0.0387162030753443,0.0489122439653445,0.0316104231209591,0.0265153787903867,0.0384905540336997,0.0679986415765224,0.0321631997318591,0.0634453928368723,0.0192758592508607,0.029608364762931,0.0513664771770609,0.0391104934561966,0.040441841914736,0.0412192509092134,0.0682212633964343,0.0464335384531918,0.0814433919972387,0.0871005588107639,0.192856747879941,0.060900984139278,0.161748380742521,0.200371047197762,0.150143034561821,0.176932236243939,0.126676901792869,0.270053961338141,0.161895491119124,0.125705210367839,0.114015497713007,0.128272423377404,0.120223209775727,0.0805775270623676,0.0944333850827992,0.196956766062769,0.339835594440329,0.203907762837206,0.2025146484375,0.0979132816709321,0.095847887870593,0.073602084455819,0.0895857851729434,0.0644812542459239,0.320930093021716,0.127427725956358,0.235913659772302,0.108491541975636,0.138192386950477,0.199337716829979,0.275268289317255
),R2_height = c(0.645737397976941,0.645737397976941,0.645737397976941),slope_height = c(value_height = 36.3572830718276,value_height = 36.3572830718276,value_height = 36.3572830718276
),intercept_height = c(5.28102549943852,5.28102549943852,5.28102549943852),RMSE_height = c(3.58862854318771,3.58862854318771,3.58862854318771
)),row.names = c(NA,-89L),class = "data.frame")

解决方法

首先，您应该创建一个仅包含标签值的 data.frame，否则您会为数据集中的每个点在其自身之上一遍又一遍地绘制标签。所以你可以创建

labeldata <- df %>% 
   distinct(date_rpm,RMSE_height,R2_height,intercept_height,slope_height)

然后当你制作标签时，你需要创建一个有效的 R plotmath 表达式的文本。您不能随意混合文本和数学符号。你可以看到它目前正在生产什么

with(df,paste0(
     'r^2 %~~%',round(R2_height,2),' RMSE %~~% ',round(RMSE_height,'\n y =',round(intercept_height,'+',round(slope_height,2 ),'x'))
#  [1] "r^2 %~~%0.65 RMSE %~~% 3.59\n y =5.28+36.36x"
#  [2] "r^2 %~~%0.65 RMSE %~~% 3.59\n y =5.28+36.36x"
#  [3] "r^2 %~~%0.65 RMSE %~~% 3.59\n y =5.28+36.36x"
#  ....  (many more lines repeated)

因此您可以看到它尝试打印相同文本的次数。而那些不是有价值的表达。你不能只在 R 表达式中有多个语句，它们之间只有一个空格，这里有一个使用简化 data.frame 的替代版本

with(labeldata,paste0(
     'atop(r^2 %~~%','~RMSE %~~% ',',y =','*x)'))
# [1] "atop(r^2 %~~%0.65~RMSE %~~% 3.59,y =5.28+36.36*x)"

现在我们只有一个标签，而且它在语法上是正确的。您可以在 geom_text like

中使用它

geom_text(
    aes(label = paste0(
      'atop(r^2 %~~%','*x)')),size = 4,x = 0.3,y = 10,col = 'black',data=labeldata,parse = T)

annotate ggplot2 r r