title: Remove Special Characters in NSString
body: <p>i am convert paragraph into words it contains many special characters like</p>
  
  <pre><code>"  , "  . `
  </code></pre>
  
  <p>how to remove this characters in nsstring and get only alphabets in nsstring</p>
  
  <p>ex
  "new" to new <code>//the special characters are change</code> </p>