Reusing Local Variable

Question

Hi Everyone, 
 
 I have a requirement where i can reuse local variable array. For Example 
 
 a!localvariable( 
 local!iterations:{1,2,3}, 
 local!value, 
 a!foreach( 
 items:local!iterations, 
 expression{ 
 append( 
 local!value, 
 fv!index 
 )})) 
 The output i need is 
 1st Iteration 
 1 
 2nd Iteration 
 1 
 2 
 3rd Iteration 
 1 
 2 
 3 
 But the output the code is generating is 
 1st Iteration 
 1 
 2nd Iteration 
 2 
 3rd Iteration 
 3. 
 I thought that local variable should be append with the value and can use for next iteration but it is initializing every time with null value rather than appendvalue. Could you please help me to get the output i need 
 
 Thanks In Advance!!!

Harshit Bumb (Appyzie) · Answer

You CANNOT update the value of a variable in an expression rule. To update a variable value, you need a user interaction to happen and that is why it is only possible in an interface or a PM. To achieve your use case, you can make this small tweak in your code and it should work. a!localVariables(
 local!iterations: { 1, 2, 3 },
 local!value,
 a!forEach(
 items: local!iterations,
 expression: enumerate(fv!index)+1
 )
)

Alex Boerescu · Answer

That is the correct behaviour - you cannot modify the value of variables outside of a foreach. You could nest two foreach to achieve this - see the code below. 
 a!localvariables(
 local!iterations: { 1, 2, 3 },
 a!forEach(
 items: local!iterations,
 expression: a!localVariables(
 local!index: fv!index,
 a!forEach(
 items: enumerate(local!index),
 expression: local!iterations[fv!index]
 )
 )
 )
)

Harshitha Mangamuri · Answer

Hi Hema, I hope this will help you in solving your issue. 
 a!localVariables(
 local!iterations: {1,2,3},
 local!res: a!forEach(
 items: local!iterations,
 expression: {
 a!forEach(
 items: enumerate(fv!index)+1,
 expression: local!iterations[fv!item]
 )
 }
 ),
 local!res
)

Mike Schmitt · Answer

I think you have a fundamental misunderstanding of what local variables are and what they do (and what they don't do). And what happens when functions act upon them. 
 A slightly simpler example: If you have a local variable of "local!asdf: {1, 2, 3}" for instance - and you call append() on it: the result of append() is simply an output of the resulting value, it does not (nor would it ever) modify the original local variable it was acting upon.