title: get value only from "UIDeviceRGBColorSpace 1 1 1 1" while using componentsSeparatedByString,sigabrt occurs?
body: <p>my string value is this 
  // The string should be something like <code>"UIDeviceRGBColorSpace 0.5 0 0.25 1"</code></p>
  
  <p>i'm parsing the string to get the color value alone </p>
  
  <pre><code> -(UIColor*)colorFromNSString:(NSString *)string {
  
  
          NSMutableArray *values = [string componentsSeparatedByString:@""];
          CGFloat red = [[values objectAtIndex:1] floatValue];
          CGFloat green = [[values objectAtIndex:2] floatValue];
         CGFloat blue = [[values objectAtIndex:3] floatValue];
        CGFloat alpha = [[values objectAtIndex:4] floatValue];
        UIColor *color = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
     //     NSLog(@"the color in string is %@",red);
         return color;
  }
  </code></pre>
  
  <p>i'm geting the error msg of sigabrt in this line </p>
  
  <pre><code>NSMutableArray *values = [string componentsSeparatedByString:@""];
  </code></pre>
  
  <p>crash log is </p>
  
  <pre><code>Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayM componentsSeparatedByString:]: unrecognized selector sent to instance 0x4b4a3e0'
  *** Call stack at first throw:
  (
      0   CoreFoundation                      0x00dcf5a9 __exceptionPreprocess + 185
      1   libobjc.A.dylib                     0x00f23313 objc_exception_throw + 44
      2   CoreFoundation                      0x00dd10bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187
      3   CoreFoundation                      0x00d40966 ___forwarding___ + 966
      4   CoreFoundation                      0x00d40522 _CF_forwarding_prep_0 + 50
      5   PhotoApp                            0x00002800 -[PhotoAppViewController colorFromNSString:] + 67
      6   PhotoApp                            0x000027b5 -[PhotoAppViewController touchesBegan:withEvent:] + 950
      7   UIKit                               0x0038d0f4 forwardMethod2 + 92
      8   UIKit                               0x002e3d41 -[UIWindow _sendTouchesForEvent:] + 395
      9   UIKit                               0x002c4c37 -[UIApplication sendEvent:] + 447
      10  UIKit                               0x002c9f2e _UIApplicationHandleEvent + 7576
      11  GraphicsServices                    0x01727992 PurpleEventCallback + 1550
      12  CoreFoundation                      0x00db0944 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
      13  CoreFoundation                      0x00d10cf7 __CFRunLoopDoSource1 + 215
  </code></pre>
  
  <p>any suggestion welcome</p>