title: Binary operator '<=' cannot be applied to operands of type 'UILabel?' and 'Double'
body: <p>Binary operator '&lt;=' cannot be applied to operands of type 'UILabel?' and 'Double'</p>
  
  <pre><code>@objc func calculate() {
      if let yourHeightTxtField = yourHeightTxtField.text, let yourWeightTxtField = yourWeightTxtField.text {
  
          if let height = Double(yourHeightTxtField), let weight = Double(yourWeightTxtField) {
              view.endEditing(true)
              Percentile.isHidden = false
              numOfPercentile.isHidden = false
              numOfPercentile.text = "\(BMI.getPercentile(forWeight: weight, andHeight: height))"
          }
      }
      if (numOfPercentile &lt;= 18.5) {
          Percentile.text = "you are underweight"
      }
  }
  </code></pre>