title: Count occurence of a word by ID in python
body: <p>Following is the content of a file,My question is how to count the number of occurences for the word "optimus" for different IDs </p>
  
  <pre><code>    ID67    DATEUID Thank you for choosing Optimus prime. Please wait for an Optimus prime to respond. You are currently number 0 in the queue. You should be connected to an agent in approximately TIMEUID.. You are now chatting with AGENTUID   0
      ID67    Optimus MEMORYUID Hi there! Welcome to Optimus prime Web Chat. How can I help you today?        1       
      ID67    Optimus DATEUID I like to pay  prepaid from CURRENCYUID with NUMBERUID expiry on whateve date. my phone no is PHONEUID 2
      ID12120 0 0 0 is the number. They are open 0/0 so you can ring them anytime. SMILEUID   1
      ID12120 Thanks Optimus, I will give them a call. Thanks for your help! HELPUID  2
      ID5552  is the number. They are open 0/0 so you can ring them anytime. SMILEUID 1
      ID5552  Thanks Optimus, I will give them a call. Thanks for your help! HELPUID  2
  
  for line in chat.txt:
     print line, ####print lines and count optimus word for the particular id..
  </code></pre>
  
  <p>Output should be like</p>
  
  <pre><code>ID67:4
  ID12120
  ID5552:1
  </code></pre>