title: Creating a table with prettytable from list of dictionaries
body: <p>I have a list of dictionaries in a form like shown below:</p>
  
  <pre><code>mylist=[{'M': 0.02788376633371408, 'G': 0.06911804019734125, 'N': 0.03952819565622443, 'K': 0.07071475441708995, 'Q': 0.03835921614374478, 'P': 0.03663450555326026, 'Y': 0.0349154656880615, 'A': 0.07679377192342901, 'S': 0.0628024724362246, 'H': 0.022690192075566464, 'L': 0.09661538710801111, 'T': 0.05419593165965927, 'V': 0.06747352986446967, 'E': 0.07257313210359605, 'D': 0.05184258066606719, 'R': 0.040929674905420405, 'I': 0.07369188519211607, 'C': 0.007873397007477256, 'F': 0.04502555876896655, 'W': 0.010337732195947861, 'X': 8.101036122520071e-07},{'M': 0.026012299035369776, 'S': 0.08222942122186495, 'Q': 0.04284397106109325, 'L': 0.0842411575562701, 'T': 0.05967950160771704, 'A': 0.06484501607717041, 'E': 0.06722242765273312, 'D': 0.05424099678456592, 'K': 0.06239324758842444, 'C': 0.01983110932475884, 'G': 0.054260932475884247, 'V': 0.062292363344051443, 'I': 0.059238424437299035, 'F': 0.04464646302250804, 'N': 0.04793086816720257, 'Y': 0.030552572347266882, 'W': 0.010734163987138263, 'R': 0.05250265273311897, 'H': 0.02322789389067524, 'P': 0.05107435691318328, 'U': 1.6077170418006432e-07},{'M': 0.025028481439857867, 'C': 0.018105322240839924, 'K': 0.0623929624244052, 'A': 0.06482217306201797, 'E': 0.06590914284008073, 'F': 0.043525892211680704, 'L': 0.09655372825447149, 'Y': 0.029081277835727382, 'H': 0.022226947906896288, 'R': 0.0528779816846854, 'W': 0.012560430627315015, 'V': 0.06773431004544274, 'G': 0.06567321684878855, 'D': 0.05337478602998517, 'S': 0.0884704243710007, 'I': 0.054255127815674375, 'N': 0.04415657018840295, 'T': 0.051248648472095336, 'P': 0.04731066098107924, 'Q': 0.03469191471955296}]
  </code></pre>
  
  <p>Now I want to create a table, where keys will be names of columns and values will be rows. I will add that mylist has 8 elements. I tried it this way:</p>
  
  <pre><code>column_names=[mylist[0].keys()]
  
  for i in column_names:
      for k in range(0,8):
          x.add_column(column_names,mylist[k][column_names])
  print(x)
  </code></pre>
  
  <p>I get an error: <code>TypeError: unhashable type: 'list'</code> </p>
  
  <p>The thing to note is that sometimes there are more keys in one dictionary than in the other, then I would like the cell to be empty.</p>
  
  <p>Any help appreciated!</p>