title: Marking the entire group if condition is true for a single row
body: <p>I have a dataframe which has Dates and public holidays </p>
  
  <pre><code>Date    WeekNum Public_Holiday
  1/1/2015    1   1
  2/1/2015    1   0
  3/1/2015    1   0
  4/1/2015    1   0
  5/1/2015    1   0
  6/1/2015    1   0
  7/1/2015    1   0
  8/1/2015    2   0
  9/1/2015    2   0
  10/1/2015   2   0
  11/1/2015   2   0
  12/1/2015   2   0
  13/1/2015   2   0
  </code></pre>
  
  <p>I have to create a conditional column named Public_Holiday_Week, which should return 1, if that particular week has a public holiday </p>
  
  <p>And I want to see an output like this </p>
  
  <pre><code>Date    WeekNum Public_Holiday  Public_Holiday_Week
  1/1/2015    1   1               1
  2/1/2015    1   0               1
  3/1/2015    1   0               1
  4/1/2015    1   0               1
  5/1/2015    1   0               1
  6/1/2015    1   0               1
  7/1/2015    1   0               1
  8/1/2015    2   0               0
  9/1/2015    2   0               0
  10/1/2015   2   0               0
  11/1/2015   2   0               0
  12/1/2015   2   0               0
  13/1/2015   2   0               0
  </code></pre>
  
  <p>I tried using np.where</p>
  
  <pre><code>df['Public_Holiday_Week'] = np.where(df['Public_Holiday']==1,1,0)
  </code></pre>
  
  <p>But it applies 0 for other days of the week when it is not a public holiday.</p>
  
  <p>Do I have to apply rolling here? Appreciate your help</p>