title: Appending array rows to .txt file in Python 3
body: <p>I am simply trying to put my 11-column, single row of values into a text file that I can append new rows to. I am used to python 2.7 and I do not understand why my <code>np.savetxt</code> is not behaving the same as previously.</p>
  
  <p>I know that this will create my text file without having any type errors:</p>
  
  <pre><code>with open("testtext.txt", "wb") as myfile:
      np.savetxt(myfile, mydata, fmt="%.5f", delimiter=' ', newline=' ')
  </code></pre>
  
  <p>However when I then run my code to receive my new data that I need to append, and I change it to:</p>
  
  <pre><code>with open("testtext.txt", "ab") as myfile:
      np.savetxt(myfile, mynewdata, fmt="%.5f", delimiter=' ', newline=' ')
  </code></pre>
  
  <p>It does not put <code>mynewdata</code> into a new row. I have input <code>\n</code> into newline, I have tried <code>" "</code> instead of <code>' '</code>, I have tried <code>\r\n</code> but that was a longshot.. Please help, I feel like this should be a simple thing. Thank you.</p>