Can anyone explain how this Variables script works please?

[jblomqvist]

Hello

Below is a script I found on the internet to load variables:

//====================================================================================================

// COMMON VARIABLES LOAD SCRIPT

//

// Sample script to load the common variables into the application.  

// You may wish to store these in Excel (as was done here) or in a database or flat file. It won't

// impact the usage of the variables.   Once they are read into the application here they are then

// created as document variables for this application with the second section of code below.  

//====================================================================================================

CommonVariables:

LOAD

     VariableName,

     VariableValue

FROM

[Variables.xlsx]

(ooxml, embedded labels, table is Sheet1);

// ---------------------------------------------------------------------------

// This code converts the variables from table values to document variables

// ---------------------------------------------------------------------------

Let RowCount = NumMax(NoOfRows('CommonVariables'),0)-1;

For i=0 to '$(RowCount)'

  Let TempVarName = peek('VariableName',$(i),'CommonVariables');

  Let TempVarValue = peek('VariableValue',$(i),'CommonVariables');

  Let $(TempVarName) = '$(TempVarValue)';

Next

// -------------------------------------------------------------------------------------------

// You can drop the CommonVariables table if you don't want to use it for display in the app

// -------------------------------------------------------------------------------------------

DROP TABLE CommonVariables;

//------------------------------------------------------------------------

Ths script above works but I do not understand how the variables are stored as Document Variables.

What part of the For Next loop does that? How does QlikView know that it needs to store this as Document Variables?

[lironbaram]

For i=0 to '$(RowCount)'

  Let TempVarName = peek('VariableName',$(i),'CommonVariables'); - this row assign the desired name for the variable to

  temporary variable

  Let TempVarValue = peek('VariableValue',$(i),'CommonVariables'); - this row assign the desired value for the variable to  temporary variable

  Let $(TempVarName) = '$(TempVarValue)';- this row creates the variable with the parameters from the previous rows

Next

in general a LET\SET Statement means you are creating a variable

[jblomqvist]

Hi Liron,

Thanks. Why do we need a -1 at the end of Let RowCount statement?

[Peter_Cammaert]

Because peeks run from 0 to RowCount-1 (peek() index is 0-based). Otherwise you'll run past the end of the table...

[lironbaram]

because the row count starts from 1 and the

variable i starts from 0

[Peter_Cammaert]

See a similar discussion here: variables evalution confusion?