title: python to find sub string inside string
body: <p>I am new to python and I have simple problem with code below
  the code supposed to give the result 'x100' while it is 'x10' and 'x100'.How to get the result as expected.</p>
  
  <pre><code>test_list=['x10','x50','x100']
  text='this text has x100 only'
  for i in test_list:
      if  text.find(i)!=-1:
          print "found "+i 
  &gt;&gt;&gt; 
  found x10
  found x100
  &gt;&gt;&gt; 
  </code></pre>