title: count the frequency of elements in list of lists in Python
body: <p>Say, I have the following sorted list of lists :</p>
  
  <p>List 1  : (12,24,36)</p>
  
  <p>List 2  : (3,5,12,24)</p>
  
  <p>List 3  : (36,41,69)</p>
  
  <p>I want to find out the frequency of each element in the entire list of lists. I came up with an ugly module for the same in python but I was wondering if there is some library function..</p>
  
  <p>Edit : Please find the code below </p>
  
  <pre><code>def find_frequency(transactions,list):
      freq = 0
      for items_transaction in transactions:
          flag = 0
          for candidate in list:
              if candidate not in items_transaction:
                  flag = 1
                  break
          if flag == 0:
              freq += 1
      return freq
  </code></pre>