r - 使用独特的 RMarkdown 标题创建多个图

Question

使用 spineplot在 R 中，我试图创建一系列图，将一些潜在的协变量与年龄类别进行比较，以便我们可以进行一些初步的数据探索。我用 R Markdown 编写了这段代码，我正在使用 RStudio 将文件编织成 HTML 输出。但是，我很难让我的循环生成的每个图都有一个合适的 RMarkdown header 。我试过把 cat("## my header")在生成每个图的循环中，但由于某种原因，它只显示第一个图，而不显示其余图。它会打印出其余的内容，但不会被解释为 Markdown。

这是我的代码示例:

---
title: "Minimal Working Example"
author: "TARehman"
date: "Wednesday, August 27, 2014"
output:
  html_document:
    toc: yes
---

# Spineplots
```{r mwe, echo=FALSE, results='asis', fig.height=5, fig.width=8, dpi=300}
tempdata <- data.frame(age=c("0-1","0-1","1-3","1-3","3-7","10-15","3-7","7-10"),
                       covA=c("Class 0","Class 1","Class 3","Class 2","Class 4","Class 3","Class 1","Class 2"),
                       covB=c("Class 1","Class 3","Class 2","Class 4","Class 4","Class 1","Class 1","Class 0"),
                       covC=c("Class 3","Class 3","Class 2","Class 3","Class 1","Class 4","Class 4","Class 4"))

temp_covars <- c("covA","covB","covC")

temp_locvec <- c(0.1,0.3,0.5,0.7,0.9)
temp_labvec <- c("0-1","1-3","3-7","7-10","10-15")
temp_colvec <- rainbow(n = 5,start = 7/12,end = 9/12,alpha = 0.8)

for(x in temp_covars) {

    cat(paste("## Spineplot of",x,"vs. age groups\n",sep=" "))

    spineplot(x = tempdata[[x]],
              y = tempdata$age,
              ylab = "Age Group",
              xlab = "Class",
              col = temp_colvec,
              off = 0,
              yaxlabels = c(NA,NA,NA,NA,NA),
              main = paste("Classes of",x,"versus age groups",sep=" "))

    for(j in 1:5) {
        axis(side = 2,
             at = temp_locvec[j],
             labels = temp_labvec[j],
             col.axis = temp_colvec[j],
             font.axis = 2)
        }
    rm(j)
}
rm(list=c("x","temp_locvec","temp_labvec","temp_colvec"))
```

输出看起来像这样。

Answer 1

事实证明，您需要额外的回车。正如 Yihui 所指出的，标题需要一个空行才能被 Markdown 正确解释。在我的循环末尾添加一个简单的 cat("\n\n") 可以解决问题。

我曾尝试只添加一个换行符，但错过了需要两个换行符才能正确解释标题。

---
title: "Working Solution"
author: "TARehman"
date: "September 3, 2014"
output:
  html_document:
    toc: yes
---

# Spineplots
```{r mwe, echo=FALSE, results='asis', fig.height=5, fig.width=8, dpi=300}
tempdata <- data.frame(age=c("0-1","0-1","1-3","1-3","3-7","10-15","3-7","7-10"),
                       covA=c("Class 0","Class 1","Class 3","Class 2","Class 4","Class 3","Class 1","Class 2"),
                       covB=c("Class 1","Class 3","Class 2","Class 4","Class 4","Class 1","Class 1","Class 0"),
                       covC=c("Class 3","Class 3","Class 2","Class 3","Class 1","Class 4","Class 4","Class 4"))

temp_covars <- c("covA","covB","covC")

temp_locvec <- c(0.1,0.3,0.5,0.7,0.9)
temp_labvec <- c("0-1","1-3","3-7","7-10","10-15")
temp_colvec <- rainbow(n = 5,start = 7/12,end = 9/12,alpha = 0.8)

for(x in temp_covars) {

    cat(paste("## Spineplot of",x,"vs. age groups\n",sep=" "))

    spineplot(x = tempdata[[x]],
              y = tempdata$age,
              ylab = "Age Group",
              xlab = "Class",
              col = temp_colvec,
              off = 0,
              yaxlabels = c(NA,NA,NA,NA,NA),
              main = paste("Classes of",x,"versus age groups",sep=" "))

    for(j in 1:5) {
        axis(side = 2,
             at = temp_locvec[j],
             labels = temp_labvec[j],
             col.axis = temp_colvec[j],
             font.axis = 2)
        }
    rm(j)
    cat("\n\n")
}
rm(list=c("x","temp_locvec","temp_labvec","temp_colvec"))
```