title: Split string with zsh as in Python
body: <p>In python:</p>
  <pre class="lang-python prettyprint-override"><code>s = '1::3'
  a = s.split(':')
  print(a[0]) # '1' good
  print(a[1]) # '' good
  print(a[2]) # '3' good
  </code></pre>
  <p>How can I achieve the same effect with <code>zsh</code>?</p>
  <p>The following attempt fails:</p>
  <pre class="lang-zsh prettyprint-override"><code>string=&quot;1::3&quot;
  a=(${(s/:/)string})
  echo $a[1] # 1
  echo $a[2] # 3 ?? I want an empty string, as in Python
  </code></pre>