title: Search list: match only exact word/string
body: <p>How to match exact string/word while searching a list. I have tried, but its not correct. below I have given the <code>sample list</code>, <code>my code</code> and the <code>test results</code></p>
  
  <pre>
  list = ['Hi, hello', 'hi mr 12345', 'welcome sir']
  </pre>
  
  <p>my code:</p>
  
  <pre>
  for str in list:
    if s in str:
      print str
  </pre>
  
  <p>test results:</p>
  
  <pre>
  s = "hello" ~ expected output: 'Hi, hello' ~ output I get: 'Hi, hello'
  s = "123" ~ expected output: *nothing* ~ output I get: 'hi mr 12345'
  s = "12345" ~ expected output: 'hi mr 12345' ~ output I get: 'hi mr 12345'
  s = "come" ~ expected output: *nothing* ~ output I get: 'welcome sir'
  s = "welcome" ~ expected output: 'welcome sir' ~ output I get: 'welcome sir'
  s = "welcome sir" ~ expected output: 'welcome sir' ~ output I get: 'welcome sir'
  </pre>
  
  <p>My list contains more than 200K strings</p>