我尝试使用循环或 lapply 在 Rmarkdown 文档中创建多个绘图图形.

I try to create multiple plotly figures in a Rmarkdown document using loop or lapply.

R 脚本:

require(plotly)
data(iris)
b <- lapply(setdiff(names(iris), c("Sepal.Length","Species")),
            function(x) {
              plot_ly(iris, 
                      x = iris[["Sepal.Length"]],
                      y = iris[[x]], 
                      mode = "markers")
            })
print(b)

效果很好，但是当包含在 knitr 块中时会失败:

works well, but it fails when included in a knitr chunk:

---
output: html_document
---

```{r,results='asis'}
require(plotly)
data(iris)
b <- lapply(setdiff(names(iris), c("Sepal.Length","Species")),
            function(x) {
              plot_ly(iris, 
                      x = iris[["Sepal.Length"]],
                      y = iris[[x]], 
                      mode = "markers")
            })
print(b)
```

我尝试用 lapply eval 和 parse 的组合替换 print(b) 但只有最后一个图已显示.

I tried replacing print(b) with a combination of lapply eval and parse but only the last figure was displayed.

我怀疑存在范围/环境问题，但我找不到任何解决方案.

I suspect a scoping/environment issue but I cannot find any solution.

推荐答案

把 print(b) 放在 htmltools::tagList() 中，而不是 print(b)，例如

```{r}
library(plotly)

b <- lapply(
  setdiff(names(iris),
          c("Sepal.Length","Species")),
  function(x) {
    plot_ly(iris, 
            x = iris[["Sepal.Length"]],
            y = iris[[x]], 
            mode = "markers")
  }
)

htmltools::tagList(b)
```