检测变量的状态变化

huangapple
go评论140阅读模式
英文:

Detecting State Change for a variable

问题

我正在编写一段代码，根据阈值检测状态变化。主要目标是只在状态变化时从函数中获取返回值。以下是我目前编写的代码。如果变量的状态没有改变，我们目前会在函数的返回值中返回一个空字符串""。有没有办法在状态不变时抑制返回值，而不是返回一个空字符串？

  1. func (f *stateChange) Exec(args []interface{}, _ api.FunctionContext) (interface{}, bool) {
  2.     
  3.     m1 := args[0]
  4.     m2 := m1.([]interface{})
  5.     valarray := []float64{}
  6.     
  7.     for _, v := range m2 {
  8.         valarray = append(valarray, v.(float64))
  9.     }
  10.     
  11.     
  12.     firstval := valarray[0]
  13.     secondval := valarray[1]
  14.     
  15.     message1 := "Medium Level Alarm"
  16.     message2 := "High Level Alarm"
  17.     message3 := "Normal Operation"
  19.     message4 := "" //**空字符串**
  20.     
  21.     if secondval >= 50 && secondval < 100 && firstval < 50{
  22.     
  23.     return message1, true
  24.     }
  25.     if firstval >= 100 && secondval < 100 && secondval >= 50{
  26.     
  27.     return message1, true
  28.     }    
  29.     
  30.     if secondval >= 100 && firstval < 100{
  31.     
  32.     return message2, true    
  33.     }    
  34.     
  35.     if firstval >= 50 && secondval < 50 {
  36.     
  37.     return message3, true
  38.     
  39.     }
  40.     
  41.     return message4, true //**需要抑制此输出中的空字符串**
  42.     
  44. }
英文:

I am writing a code to detect state change based on a threshold value. Main goal is to get a return value from the function only when the state changes. Here is the code I have written so far. If the state of variable does not change currently we are returning &quot;&quot; empty string in the return value of the function. Is there a way that we can suppress the return value if the state does not changes, instead of returning &quot;&quot; (empty string)

`

  1. func (f *stateChange) Exec(args []interface{}, _ api.FunctionContext) (interface{}, bool) {
  2. 	
  3. 	m1 := args[0]
  4. 	m2 := m1.([]interface{})
  5. 	valarray := []float64{}
  6. 	
  7. 	for _, v := range m2 {
  8. 	    valarray = append(valarray, v.(float64))
  9. 	}
  10. 	
  11. 	
  12. 	firstval := valarray[0]
  13. 	secondval := valarray[1]
  14. 	
  15. 	message1 := &quot;Medium Level Alarm&quot;
  16. 	message2 := &quot;High Level Alarm&quot;
  17. 	message3 := &quot;Normal Operation&quot;
  19. 	message4 := &quot;&quot;	//**empty string**
  20. 	
  21. 	if secondval &gt;= 50 &amp;&amp; secondval &lt; 100 &amp;&amp; firstval &lt; 50{
  22. 	
  23. 	return message1, true
  24. 	}
  25. 	if firstval &gt;= 100 &amp;&amp; secondval &lt; 100 &amp;&amp; secondval &gt;= 50{
  26. 	
  27. 	return message1, true
  28. 	}	
  29. 	
  30. 	if secondval &gt;= 100 &amp;&amp; firstval &lt; 100{
  31. 	
  32. 	return message2, true	
  33. 	}	
  35. 	if firstval &gt;= 50 &amp;&amp; secondval &lt; 50 {
  36. 	
  37. 	return message3, true
  38. 	
  39. 	}
  40. 	
  41. 	return message4, true //**empty string in return need to suppress this output**
  42. 	
  44. }

`

答案1

得分: 1

抑制此输出的最佳方法是使用 nil。

  1. return nil, true
英文:

The best way to suppress this output is using nil.

  1. return nil, true

huangapple
  • 本文由 发表于 2021年7月2日 05:46:33
  • 转载请务必保留本文链接：https://go.coder-hub.com/68217293.html
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