Question

我需要有一个嵌套的“ If语句”，并且不能完全正常工作-不断出现错误-在最后一个居里括号中正确显示期望的表达式。

下面的代码是我尝试过的：

if weightLabel.text == "Weight (lbs)" {
      if pickerView == heightPicker {
            let titleRow = height[row]
             return titleRow
      } else if pickerView == weightPicker {
                let titleRow = weight[row]
                return titleRow
              }
         return ""
        else if weightLabel.text == "Weight (kgs)" {
            if pickerView == heightPicker {
                let titleRow = heightCM[row]
                return titleRow
            }
            else if pickerView == weightPicker {
                let titleRow = weightKG[row]
                return titleRow
            }
            return ""
         }
 }

有人可以看看我当前的代码和帮助吗？

Answer 1

应该是这样的：

func getWeight() -> String {
    if weightLabel.text == "Weight (lbs)" {
        if pickerView == heightPicker {
            let titleRow = height[row]
            return titleRow
        }
        else if pickerView == weightPicker {
            let titleRow = weight[row]
            return titleRow
        }
        return ""
    }
    else if weightLabel.text == "Weight (kgs)" {
        if pickerView == heightPicker {
            let titleRow = heightCM[row]
            return titleRow
        }
        else if pickerView == weightPicker {
            let titleRow = weightKG[row]
            return titleRow
        }
        return ""
    }
    return ""
}

Answer 2

由于到处都有return语句，因此可以跳过所有else

if weightLabel.text == "Weight (lbs)" {
    if pickerView == heightPicker {
        return height[row]
    }
    if pickerView == weightPicker {
        return weight[row]
    }
}

if weightLabel.text == "Weight (kgs)" {
    if pickerView == heightPicker {
        return heightCM[row]
    }

    if pickerView == weightPicker {
         return weightKG[row]
    }
}
return ""

另一种方法是使用在if / else子句中设置的局部变量，然后返回

var titleRow = ""
if weightLabel.text == "Weight (lbs)" {
    if pickerView == heightPicker {
        titleRow = height[row]
    } else if pickerView == weightPicker {
        titleRow = weight[row]
    }
} else if weightLabel.text == "Weight (kgs)" {
    if pickerView == heightPicker {
        titleRow = heightCM[row]
    } else if pickerView == weightPicker {
        titleRow = weightKG[row]
    }
}

return titleRow

Swift Nested If语句无法编译

2 个答案: