title: as.Date fails in R: 'character string is not in a standard unambiguous'
body: <p>I am working with data in <code>R</code> that I imported form <code>excel</code> format. </p>
  
  <p>I have a column (<code>isas1_3b</code>) in the dataframe (<code>LPAv1.1.1</code>) which is in the <code>character</code> format. Upon importing, the dates have changed from the format dd/mm/yy, to days (e.g., 41268). </p>
  
  <p>I have tried to convert this as below: </p>
  
  <pre><code>as.Date(LPAv1.1.1$isas1_3b, origin = "1899-12-30")
  </code></pre>
  
  <p>However, I get the following error: </p>
  
  <blockquote>
    <p>Error in charToDate(x) : character string is not in a standard unambiguous format
    4. stop("character string is not in a standard unambiguous format")
    3. charToDate(x)
    2. as.Date.character(LPAv1.1.1$isas1_3b, origin = "1899-12-30")
    1. as.Date(LPAv1.1.1$isas1_3b, origin = "1899-12-30")</p>
  </blockquote>
  
  <p>I'm not sure what I am doing wrong. After numerous searches, the above conversion is what was recommended. </p>
  
  <p>I should also add, that there are two other date columns in the original <code>excel</code> document. But they have both been read in as <code>'POSIXct''POSIXt'</code>.  </p>
  
  <p>Other info that may be relevant: </p>
  
  <pre><code>macOS 13.13.3 R 3.3.3 RStudio 1.1.419
  </code></pre>
  
  <p>Can someone please help resolve this issue... I am assuming it is something that I am doing. Please let me know if you need any more info.</p>