title: How to concatenate elements from a list with another nested list?
body: <p>I'm trying to concatenate a list with a nested list, but without using dictionary because the dictionary is not keeping the same order and this is screwing a bit what I'm doing. Not sure if this is possible,  but basically what I have is:</p>
  
  <pre><code>list1=['a','b','c','d','e']
  list2=[['1','2','3'],['4','5','6'],['7','8','9'],['T1','T2','T3'],[]]
  </code></pre>
  
  <p>and the output I need is:</p>
  
  <pre><code>[['a_1','a_2','a_3'],['b_4','b_5','b_6'],['c_7','c_8','c_9'],['d_T1','d_T2','d_T3'],['e']]
  </code></pre>
  
  <p>I'm able to do it with a dictionary with this code:</p>
  
  <pre><code>dict = dict(zip(list1, list2))
  for key,values in dict.iteritems():
      vals = dict[key]
      values = [key + '_' + str(v) for v in vals]
      test.append(values)
  </code></pre>
  
  <p>but the order is not the same, and I need to match some lists together later... So I really would prefer to avoid the dictionary part, anyone having any idea?</p>
  
  <p>Thanks!</p>