vb2Py - Select

Contents of this page:

Specific options:

General

Select blocks are replaced by if/elif/else blocks. By default a select variable is created, which is used in subsequent tests. This means that the checked value is only evaluated once per select and not once per condition. If this is not an issue then an option allows the value to be evalutated each time as required. Also by default, a numeric index is appended to the select variable to prevent clashed for nested Select constructs.

The conversion handles multiple values per case and even range settings.

Default Conversion

VBPython

Select Case Value
    Case 1
        DoOne
    Case 2
        DoTwo
    Case 3, 4
        DoThreeOrFour
    Case 5 To 10
        DoFiveToTen
    Case Else
        DoElse
End Select




    _select5 = Value
    if (_select5 == 1):
        DoOne()
    elif (_select5 == 2):
        DoTwo()
    elif (_select5 == 3) or (_select5 == 4):
        DoThreeOrFour()
    elif (5 <= _select5 <= 10):
        DoFiveToTen()
    else:
        DoElse()

List of Options

Here are the options in the INI file:

[Select]
# Once or EachTime, how many times to evaluate the case variable  
EvaluateVariable = Once
# Name of select variable (only used if EvaluateVariable is Once)
SelectVariablePrefix = _select
# Yes or No, use numeric index on select variable (needed if you every have nested Selects and EvaluateVariable = Once)
UseNumericIndex = Yes

EvaluateVariable

Syntax: EvaluateVariable = Once | EachTime

The default behaviour is to evaluate the select expression once at the start of the block. By setting this option to EachTime you can force the expression to be evaluated for each if/elif statement. This generally looks cleaner but can lead to undesired side effects or slow run times depending on how expensive 1 the expression is to calculate.

VBPython

' VB2PY-Set: Select.EvaluateVariable = EachTime
Select Case Value
    Case 1
        DoOne
    Case 2
        DoTwo
    Case 3, 4
        DoThreeOrFour
    Case 5 To 10
        DoFiveToTen
    Case Else
        DoElse
End Select
' VB2PY-Unset: Select.EvaluateVariable




    if (Value == 1):
        DoOne()
    elif (Value == 2):
        DoTwo()
    elif (Value == 3) or (Value == 4):
        DoThreeOrFour()
    elif (5 <= Value <= 10):
        DoFiveToTen()
    else:
        DoElse()

SelectVariablePrefix

Syntax: SelectVariablePrefix = name

When EvaluateVariable is set to Once, this option determines the prefix used to name the variable used in the select. If UseNumericIndex is set to No then this option sets the variable name used, otherwise this is the prefix and the final variable will also include a unique ID number.

VBPython

' VB2PY-Set: Select.SelectVariablePrefix = selectVariable
Select Case Value
    Case 1
        DoOne
    Case 2
        DoTwo
    Case 3, 4
        DoThreeOrFour
    Case 5 To 10
        DoFiveToTen
    Case Else
        DoElse
End Select
' VB2PY-Unset: Select.SelectVariablePrefix




    selectVariable7 = Value
    if (selectVariable7 == 1):
        DoOne()
    elif (selectVariable7 == 2):
        DoTwo()
    elif (selectVariable7 == 3) or (selectVariable7 == 4):
        DoThreeOrFour()
    elif (5 <= selectVariable7 <= 10):
        DoFiveToTen()
    else:
        DoElse()

UseNumericIndex

Syntax: UseNumericIndex = Yes | No

When EvaluateVariable is set to Once, this option determines whether a unique ID number is appended to the SelectVariablePrefix to determine the variable name used to hold the select expression. If used, the index is incremented for each select constuct found. This option is always required to be Yes where the code includes nested Select blocks and EvaluateVariable is set to Once. If neither of these conditions applies then it is safe to set this to No

VBPython

' VB2PY-Set: Select.UseNumericIndex = No
Select Case Value
    Case 1
        DoOne
    Case 2
        DoTwo
    Case 3, 4
        DoThreeOrFour
    Case 5 To 10
        DoFiveToTen
    Case Else
        DoElse
End Select
' VB2PY-Unset: Select.UseNumericIndex




    _select = Value
    if (_select == 1):
        DoOne()
    elif (_select == 2):
        DoTwo()
    elif (_select == 3) or (_select == 4):
        DoThreeOrFour()
    elif (5 <= _select <= 10):
        DoFiveToTen()
    else:
        DoElse()
[1]Expensive as in CPU time.