title: Need to replace emoji characters with their Unicode value
body: <p>I'm new to python and currently i'm working with project which requires to analyse emojis in user comments.
  Their I need to replace emojis in a string with their unicode values.
  Here is my code</p>
  
  <pre><code>import re
  
  RE_EMOJI = re.compile('[\U00010000-\U0010ffff]', flags=re.UNICODE)
  
  def strip_emoji(text):
      return RE_EMOJI.sub(r'', text)
  
  print(strip_emoji('hi '))
  </code></pre>
  
  <p>Sample output</p>
  
  <pre><code> hi
  </code></pre>
  
  <p>This code removes the emojis on string, But I need to replace them with their unicode value.</p>
  
  <p>Expected output</p>
  
  <pre><code>hi U0001F600 U0001F601
  </code></pre>