title: based on object value how do i get NSMutableArray index value
body: <p>How do i get index value from NSMutableArray.</p>
  
  <p>I got <code>NSString *stringValue=@"e";</code></p>
  
  <p>And my <code>NSMutableArray *arrayValue=[[NSMutableArray alloc]init];</code></p>
  
  <pre><code>[arrayValue addobject:@"a"];
  [arrayValue addobject:@"b"];
  [arrayValue addobject:@"c"];
  [arrayValue addobject:@"d"];
  [arrayValue addobject:@"e"];
  [arrayValue addobject:@"f"];
  [arrayValue addobject:@"g"];
  </code></pre>
  
  <p>I want to get array index value based on string value.</p>
  
  <p>How to do</p>
  
  <p>@thanks in advance.</p>