title: Shiny error: provided 10 variables to replace 1 variables
body: <p>Unfortunately I can't use my actual data.frame since it is not mine and is copyrighted, but I will try to explain as best as I can</p>
  
  <p>I have a data.frame that contains a column with unique strings.
  when I do datatable(mydf) in the Rstudio console, it shows me the correct table in viewer. However, when I do the same in shiny I get this warning:</p>
  
  <p>Warning in <code>[&lt;-.data.frame</code>(<code>*tmp*</code>, , j, value = list("ECDTM-12 Trimmed eTAG truncated after Fn F232C No Stop CRLF2 transcript variant 1 NM_022148_3",  :
  provided 10 variables to replace 1 variables</p>
  
  <p>essentially what it does is it takes the first string in that column "ECDTM-12 Trimmed eTAG truncated after Fn F232C No Stop CRLF2 transcript variant 1 NM_022148_3" and overrides every other string in that row with this string, instead of showing what those rows actually contain</p>
  
  <p>some maybe helpful code:</p>
  
  <pre><code>library(shiny)
  library(shinythemes)
  library(shinycssloaders)
  library(dplyr)
  library(readr)
  library(xlsx)
  library(openxlsx)
  library(ggplot2)
  library(reshape2)
  library(ggthemes)
  library(DT)
  set.seed(1)
  </code></pre>
  
  <p>code in the UI function:</p>
  
  <pre><code>fluidRow(column(12, align="center", withSpinner(dataTableOutput("partTables")
  </code></pre>
  
  <p>code in the server function:</p>
  
  <pre><code>Lib_P1_P2 &lt;- reactive(if(LibName() == "1.1A" | LibName() == "1.1B" | LibName() == "2.1"){readRDS(paste0("data/",input$library," P1_P2.rds"))})    
  output$partTables &lt;- renderDataTable({
      datatable(Lib_P1_P2(),options=list(pagelength=10), rownames = FALSE, escape = FALSE) 
  })
  </code></pre>
  
  <p>I added set.seed(1) and escape=FALSE after I saw this question:
  <a href="https://stackoverflow.com/questions/48875943/r-shiny-renderdatatable-issue">R Shiny renderDataTable issue</a> but that didn't work either..</p>
  
  <p>If I've left out any important info, let me know I'd be happy to provide.
  I'm new to stackoverflow so excuse my newbie-ness.</p>