求助：如何为参数化R Markdown的sliderInput设置日期型min和max

在参数化R Markdown中设置日期输入的sliderInput时触发错误：Error in min(value) : invalid 'type' (list) of argument。不通过参数运行时，依赖YAML里的value:配置能正常工作，但使用参数运行就报错。

错误栈信息：

Warning: Error in min: invalid 'type' (list) of argument
  47: validate_slider_value
  46: <Anonymous>
  44: param.ui
  43: FUN
  42: lapply
  41: server
   4: <Anonymous>
   2: rmarkdown::knit_params_ask
   1: knit_with_parameters
Error in min(value) : invalid 'type' (list) of argument

原R Markdown代码：

---
title: "Salmon Program"
date: "`r format(Sys.Date())`"
output:
  pdf_document:
    toc: yes
    toc_depth: '4'
    keep_md: yes
params:
  glimpse: no
  Runs:
    label: Salmon Runs
    value:
    - W
    - S
    - F
    - L
    input: select
    choices:
    - W
    - S
    - F
    - L
    multiple: yes
  Dates:
    input: slider
    min: as.Date("2012-01-01") #此处报错
    max: as.Date("2012-01-04")
    value: 
    - !r as.Date("2012-01-01")
    - !r as.Date("2012-01-04")
    step: 1
---

# Chinook Runs in the Columbia River

```{r}
knitr::opts_chunk$set(out.width = '100%', fig.height = 4, fig.align='center',warning = FALSE, message = FALSE,comment="",echo = FALSE) 
library('here')
library('tidyverse')

Import datasets #

## Subset to variables of interest
salmon2$SampleDate <- as.Date(salmon2$SampleDate,"%m/%d/%Y")
salmon2 <- salmon2 %>% 
  filter(race %in% params$Runs,
         SampleDate >= params$Dates[[1]] & SampleDate <= params$Dates[[2]])

# 解决方案
问题根源是YAML参数里的`min`和`max`配置未被正确解析：直接写`as.Date()`会被当作普通字符串处理，但`value`用了`!r`前缀让系统识别为R表达式并解析成日期类型，两者类型不匹配触发错误。

修改方式：
- 给`min`和`max`也加上`!r`前缀，让R Markdown正确解析这两个日期表达式
- （可选）用`between()`函数简化日期过滤逻辑，代码更简洁

### 修改后的YAML参数部分
```yaml
params:
  glimpse: no
  Runs:
    label: Salmon Runs
    value:
    - W
    - S
    - F
    - L
    input: select
    choices:
    - W
    - S
    - F
    - L
    multiple: yes
  Dates:
    input: slider
    min: !r as.Date("2012-01-01")
    max: !r as.Date("2012-01-04")
    value: 
    - !r as.Date("2012-01-01")
    - !r as.Date("2012-01-04")
    step: 1

简化后的过滤代码 #

salmon2 <- salmon2 %>% 
  filter(race %in% params$Runs,
         between(SampleDate, params$Dates[[1]], params$Dates[[2]]))

内容的提问来源于stack exchange，提问作者Salvador