title: Create combinations from two lists and create dictionary with separate key in Python
body: <p>I have two lists
  t1 = ['C1', 'C2', 'C3']
  t2 = ['raising', 'falling', 'constant']</p>
  <p>using two lists I want output as follows. with all the possible combinations</p>
  <pre><code>{
    'regime_1' : {
      'c1' : 'rising',
      'c2' : 'falling',
      'c3' : 'constant'
    },
      'regime_2' : {
      'c1' : 'rising',
      'c2' : 'falling',
      'c3' : 'falling'
    }
  }
  </code></pre>
  <p>Elements in t1 list should not be repeated inside &quot;regime&quot; key. I have wrote the following code in python.</p>
  <pre><code>import itertools
  t1 = ['C1', 'C2', 'C3']
  t2 = ['raising', 'faling', 'constant']
  combos = [str(i) +&quot;:&quot;+ str(n) for i in t1 for n in t2]
  combinations = dict((&quot;regime_&quot;+str(i+1),c) for i,c in enumerate(combos))
  </code></pre>
  <p>but the out put I get is</p>
  <pre><code>{'regime_1': 'C1:raising', 'regime_2': 'C1:faling', 'regime_3': 'C1:constant', 'regime_4': 'C2:raising', 'regime_5': 'C2:faling', 'regime_6': 'C2:constant', 'regime_7': 'C3:raising', 'regime_8': 'C3:faling', 'regime_9': 'C3:constant'}
  </code></pre>
  <p>Thank you</p>