title: Read excel file with formulas in cells into R
body: <p>I was trying to read an excel spreadsheet into R data frame. However, some of the columns have formulas or are linked to other external spreadsheets. Whenever I read the spreadsheet into R, there are always many cells becomes NA. Is there a good way to fix this problem so that I can get the original value of those cells?</p>
  
  <p>The R script I used to do the import is like the following:</p>
  
  <pre><code>options(java.parameters = "-Xmx8g")
  library(XLConnect)
  # Step 1 import the "raw" tab
  path_cost = "..."
  wb = loadWorkbook(...)
  raw = readWorksheet(wb, sheet = '...', header = TRUE, useCachedValues = FALSE)
  </code></pre>