title: How to parse JSON string to struct
body: <p>I have <code>struct</code> of Request, value is optional:</p>
  
  <pre><code>type Request struct {
      Operation string      `json:"operation"`
      Key string            `json:"key"`
      Value string          `json:"value"`
  }
  </code></pre>
  
  <p>And function that should parse json string to struct^ </p>
  
  <pre><code>go func() {
      s := string("{'operation': 'get', 'key': 'example'}")
      data := Request{}
      json.Unmarshal([]byte(s), data)
      log.Printf("Operation: %s", data.Operation)
  }
  </code></pre>
  
  <p>For some reason data.Operation is empty. What is wrong here?</p>