title: How to convert NSMutableArray Object's NSString data into lowercase in iOS?
body: <p>I am working with sqlite database.
  I retrieve text data from sqlite database into NSMutableArray named myArray.
  In that myArray variable, there is a column named "info" with text data.
  After i retrieve that data into NSMutableArray , i would like to convert all of text data from sqlite database into lowercase.
  I wrote following code in searchBar's textDidChange Event like that.</p>
  
  <pre><code>NSInteger counter = 0;
      for(NSString *nameMe in myArray)
      {
          NSRange r = [[nameMe lowercaseString] rangeOfString:[searchText lowercaseString]];
  
          if(r.location != NSNotFound)
          {
              if(r.location== 0)
              {
                  [tableData addObject:nameMe];
              }
          }
  
          counter++;
      }
  </code></pre>
  
  <p>However there is a error occurring in lowercaseString.</p>
  
  <p>This error is </p>
  
  <pre><code>2012-03-31 16:28:18.217 SqliteTest[1812:f803] -[MyInfoClass lowercaseString]: unrecognized selector sent to instance 0x6da9210
  2012-03-31 16:28:18.276 SqliteTest[1812:f803] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[MyInfoClass lowercaseString]: unrecognized selector sent to instance 0x6da9210'
  </code></pre>
  
  <p>I think that compiler doesn't know how to convert object data into lowercase.
  How can i solve that?
  Can i convert object (NSString) data into lowercase.
  If it can be,Please let me know how to do that.
  Thanks you for your helping.</p>