title: Add business days without Saturday sunday and specific holidays in R
body: <p>I want to add days to a date in R, except Saturdays and Sundays and specific holidays. Suppose I have a dateset :</p>
  
  <pre><code>d &lt;- dmy("25-7-2016","26-7-2016")
  days &lt;- c(3:4) 
  data &lt;- data.frame(d,days)
  data
  </code></pre>
  
  <p>I want to add #days (days column) to a date (d column) I have tried the following code:</p>
  
  <pre><code>library(bizdays)
  library(lubridate)
  cal &lt;- Calendar(weekdays=c('sunday', 'saturday'))
  data$f &lt;- offset(d, days, cal)
  data
  </code></pre>
  
  <p>I can get the days without considering Saturdays and Sundays. But I want to exclude a specific holiday i.e. 27-7-2016. I tried to incorporate this specific holiday but getting an error. The code which I tried is as follows:</p>
  
  <pre><code>holiday &lt;- dmy("27-7-2016")
  cal &lt;- Calendar(holiday,weekdays=c('sunday', 'saturday'))
  data$f &lt;- offset(d, days, cal)
  data
  </code></pre>
  
  <p>Could you please help me to get is solved. Thanks in anticipation!</p>