title: How to find starting index of a string if it contains any element from a list of substrings
body: <p>Suppose, I have a list of substring below:</p>
  <pre><code>my_list = [&quot;am&quot;, &quot;is&quot;, &quot;are&quot;]
  </code></pre>
  <p>I want to search elements of this list in a string. If the string includes any item from the list, then starting index of this substring in the string should be printed.</p>
  <p>The string is:</p>
  <pre><code>s = &quot;I am a Python developer.&quot;
  </code></pre>
  <p>It is obvious that the string contains <code>&quot;am&quot;</code> and starting index of this substring in string is <code>2</code>.</p>
  <p>Once I thought to use:</p>
  <pre><code>if &quot;am&quot; in s:
      print(s.find(&quot;am&quot;))
  </code></pre>
  <p>but I limited searching operation by only one element of list. There can be at most an item from list in the string.</p>