title: How to create an empty matrix in R?
body: <p>I am new to R. I want to fill in an empty matrix with the results of my <code>for</code> loop using <code>cbind</code>. My question is, how can I eliminate the NAs in the first column of my matrix. I include my code below: </p>
  
  <pre><code>output&lt;-matrix(,15,) ##generate an empty matrix with 15 rows, the first column already filled with NAs, is there any way to leave the first column empty?
  
  for(`enter code here`){
    normF&lt;-`enter code here`
    output&lt;-cbind(output,normF)
  }
  </code></pre>
  
  <p>The output is the matrix I expected. The only issue is that its first column is filled with NAs. How can I delete those NAs?</p>