title: Reverse string time and space complexity
body: <p>I have written different python codes to reverse a given string. But, couldn't able to figure the which one among them is efficient. Can someone point out the differences between these algorithms using time and space complexities?</p>
  
  <pre><code>def reverse_1(s):
        result = ""
        for i in s : 
            result = i + result
        return result
  
  def reverse_2(s): 
        return s[::-1]
  </code></pre>
  
  <p>There are <a href="https://stackoverflow.com/questions/931092/reverse-a-string-in-python">already some solutions out there</a>, but I couldn't find out the time and space complexity. I would like to know how much space <code>s[::-1]</code> will take? </p>