title: R: argument matches multiple formal arguments
body: <p>I tried to read-in data from a excel file which contains multiple spread sheets.</p>
  
  <pre><code>    setwd("C:/Users/XXX/XXX")
      getwd()
      rm(list=ls())
  
      require(xlsx)
      df =read.xlsx("data.csv",sheet=3, colNames = TRUE)
  </code></pre>
  
  <p>once I run this code, it always come back with this error message :</p>
  
  <pre><code>    Error in read.xlsx("dt.csv", sheet = 3,  :argument 2 matches multiple formal arguments
  </code></pre>
  
  <p>I don't know what to do. Please help, thanks.</p>