title: best way to iterate through elements of pandas Series
body: <p>All of the following seem to be working for iterating through the elements of a pandas Series. I'm sure there's more ways of doing it. What are the differences and which is the best way?</p>
  <pre class="lang-py prettyprint-override"><code>import pandas
  
  
  arr = pandas.Series([1, 1, 1, 2, 2, 2, 3, 3])
  
  # 1
  for el in arr:
      print(el)
  
  # 2
  for _, el in arr.iteritems():
      print(el)
  
  # 3
  for el in arr.array:
      print(el)
  
  # 4
  for el in arr.values:
      print(el)
  
  # 5
  for i in range(len(arr)):
      print(arr.iloc[i])
  </code></pre>