R脚本可运行代码在R Markdown编织时出现解析错误

错误信息 #

Quitting from lines 22-24 (PalmerPenguins.Rmd)
Error in parse(text = x, srcfile = src) : :2:46: unexpected '='
1: ggplot(data = penguins) + geom_point(mapping = aes(x = body_mass_g, y = flipper_length_mm)+
2: color =
^
Calls: ... -> parse_all -> parse_all.character -> parse
Execution halted

错误原因 #

• 第一个可视化代码块语法断裂：geom_point中aes()函数未闭合括号，且错误将固定颜色参数color = "purple"放在aes()的连接加号后，导致代码无法被正确解析。
• 最后一个代码块存在冗余符号：geom_point(aes(shape=species, color=sex), )末尾多了一个逗号，R脚本运行时可能容错，但R Markdown编织时会触发解析错误。

解决方法及修正代码 #

修正第一个可视化代码块 #

将固定颜色参数移到aes()外部（非变量映射无需放入aes），并闭合aes()的括号：

ggplot(data = penguins) + 
  geom_point(mapping = aes(x = body_mass_g, y = flipper_length_mm), color = "purple")

修正最后一个代码块 #

去掉geom_point末尾的多余逗号：

ggplot(data = penguins, aes(x = body_mass_g, y = flipper_length_mm)) +
  geom_point(aes(shape=species, color=sex))

完整修正后的R Markdown代码 #

---
title: "ggplot_hook"
author: "Bill"
date: "2023-03-13"
output: html_document
---

## Setting up my environment  
Notes: setting up my R environment by loading the 'tidyverse' and 'palmer penguins' packages  

```{r loading packages}
library(tidyverse)
library(palmerpenguins)

Visualizations #

Here we will go through a series of visualizations

Flipper and body mass in purple #

Here, we plot flipper length against body mass

ggplot(data = penguins) + 
  geom_point(mapping = aes(x = body_mass_g, y = flipper_length_mm), color = "purple")

Flipper and body mass by species #

Here, we plot flipper length against body mass and we look at breakdown by species

ggplot(data = penguins, aes(x = body_mass_g, y = flipper_length_mm)) +
  geom_point(aes(shape=species))

Flipper and body mass by species and sex #

Here, we plot flipper length against body mass and look at the breakdown by species and sex

ggplot(data = penguins, aes(x = body_mass_g, y = flipper_length_mm)) +
  geom_point(aes(shape=species, color=sex))

内容的提问来源于stack exchange，提问作者Bill_Stevenson1968