title: How to make B.C. Date format in R
body: <p>I have string like <code>1/1/-2150</code>. How to make <code>Date</code> format from that in R <br></p>
  
  <p><code>lubridate</code> back:<br></p>
  
  <pre><code>library(lubridate)
  dmy("1/1/-2150")
  [1] "2150-01-01"
  
  as.Date("1/1/-2150",format="%d/%m/%Y")
  [1] NA
  </code></pre>
  
  <p>Now <code>1/1/-2150</code> have class character. <br>I need same value but with class <code>Date</code><br>
  Thanks</p>
  
  <p><strong>UPDATE</strong> <br>
  Something like that, but using <code>lubridate</code> if it possible</p>
  
  <pre><code>minus=as.numeric(dmy("1/1/-2150"))
  x&lt;-as.numeric(ymd("0000-1-1"))
  dt=as.Date(x*2-minus,origin="1970-01-01")+days(1) 
  str(dt)
  Date[1:1], format: "-2150-01-01"
  </code></pre>