VBScript循环建议

Question

sqlRows = rst.GetRows()
i = 0

For Each element In sqlRows
    If i > 0 And i < sizeOfState + 1 Then 
        SmartTags("visu_state_on")(i - 1) = element
    ElseIf i > sizeOfState And i < 2 * sizeOfState + 1 Then
        SmartTags("visu_state_off")(i - sizeOfState - 1) = element
    ElseIf i > (2 * sizeOfState ) And i < 2 * sizeOfState + sizeOfMeasurement + 1 Then
        SmartTags("visu_limits_right")(i - (2 * sizeOfState - 1)) = element
    ElseIf i > 2 * sizeOfState + sizeOfMeasurement And i < 2 * (sizeOfStanja + sizeOfMeasurement ) + 1 Then
        SmartTags("visu_limits_left")(i - (2 * sizeOfState + sizeOfMeasurement )) = element
    End If

    i = i + 1
Next

With code above I'm looping through array sqlRows and with variable i I'm filling other four arrays with data from sqlRows .

This solution works but I'm wondering is there more elegant way to achieve the same.

• sqlRows is array with dimensions 343x1,
• visu_state_on is array with dimensions 8x1,
• visu_state_off is array with dimensions 8x1,
• visu_limits_right is array with dimensions 160x1,
• visu_limits_left is array with dimensions 160x1,

and variables sizeOfState and sizeOfMeasurement are just there that I can calculate indexes for these four arrays.

Answer 1

For one thing you can remove the first clause from each of your conditions, because they will always be true

• i starts with the value 0 and is always incremented, so the value will never be less than zero.
• If a value is not less than n + 1 (condition in previous ElseIf ) then it's guaranteed to be greater than n .

Also, VBScript does have a <= comparison operator, so it's better to compare i <= n rather than i < n + 1 .

I would also recommend calculating values that won't change inside the loop just once outside the loop. Re-calculating them with each loop cycle is a waste of resources.

Adding an Else branch to handle values greater than 2 * (sizeOfStanja + sizeOfMeasurement) might be a good idea too.

sqlRows = rst.GetRows()
i = 0

ref1 = 2 * sizeOfState
ref2 = ref1 + sizeOfMeasurement
ref3 = 2 * (sizeOfStanja + sizeOfMeasurement)

For Each element In sqlRows
  If i <= sizeOfState Then 
    SmartTags("visu_state_on")(i - 1) = element
  ElseIf i <= ref1 Then
    SmartTags("visu_state_off")(i - sizeOfState - 1) = element
  ElseIf i <= ref2 Then
    SmartTags("visu_limits_right")(i - ref1 + 1) = element
  ElseIf i <= ref3 Then
    SmartTags("visu_limits_left")(i - ref2) = element
  Else
    'handle i > ref3 here
  End If

  i = i + 1
Next