Python list of tuples
<pre><code>L1 = ['A', 'B', 'C', 'D'] 
L2 = [('A', 10)], ('B', 20)]
</code></pre>

<p>Now from these two list how can i generate common elements</p>

<pre><code>output_list = [('A', 10), ('B', 20), ('C', ''), ('D', '')]
</code></pre>

<p>How can i get output_list using L1 and L2?</p>

<p>I tried the following</p>

<pre><code>  for i in L2:
    for j in L1:
       if i[0] == j:
           ouput_list.append(i)
       else:
           output_list.append((j, ''))
</code></pre>

<p>But i'm not getting the exact out which i want</p>
