title: NSPredicate - Unable to parse the format string
body: <p>I am trying to write a <code>NSPredicate</code> to fetch rows with my_column value with this string "<code>193e00a75148b4006a451452c618ccec</code>" and I get the below crash.</p>
  
  <blockquote>
    <p>Terminating app due to uncaught exception
    'NSInvalidArgumentException', reason: 'Unable to parse the format
    string "my_column=193e00a75148b4006a451452c618ccec"'</p>
  </blockquote>
  
  <p>My predicate statement</p>
  
  <pre><code>fetchRequest.predicate=[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"%@==\"%@\"",attributeName,itemValue]];
  </code></pre>
  
  <p>also tried this</p>
  
  <pre><code>fetchRequest.predicate=[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"%@ == %@",attributeName,itemValue]];
  </code></pre>
  
  <p>this</p>
  
  <pre><code>fetchRequest.predicate=[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"%@ = %@",attributeName,itemValue]];
  </code></pre>
  
  <p>and this</p>
  
  <pre><code>fetchRequest.predicate=[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"%@=\"%@\"",attributeName,itemValue]];
  </code></pre>
  
  <p>Please help.</p>
  
  <p><strong>I found out this, when I was trying with Martin R's answer</strong></p>
  
  <pre><code>fetchRequest.predicate=[NSPredicate predicateWithFormat:@"%@==%@",attributeName,itemValue];
  </code></pre>
  
  <p><strong>attributeName I pass comes with a ' ' so I took off attributeName and hardcoded it, then it works fine.</strong></p>