Create an interactive list in a Wolfram notebook that choosing its items make a change in calculations

Question

I have 3 variables. I want to create an interactive list of items in a Wolfram notebook that if I choose each item, functions that are written by myself change the value of the variables and recalculate all the expressions. For example items are a b c and the variables are a1 a2 a3. If I choose item a, I want item a to become equal to b, etc. Then all related calculations should automatically be updated. I was wondering if anyone can help me in creating such a functionality.

Answer 1

Quick solution

Create a slider for 'a' between 0.1 and 1; you can change the slider's value as shown in the animation.

{Slider[Dynamic[a], {0.1, 1}], Dynamic[a]}

Now create a plot for Sin[a x]. The Plot is wrapped inside a Dynamic[ ... ] block so that it refreshes automatically when 'a' changes. Evaluate the cell.

Dynamic[
 Plot[Sin[a x], {x, 0, 2 \[Pi]}, 
  PlotTheme -> "Monochrome",
  GridLines -> Automatic,
  PlotRange -> {{0, 2 \[Pi]}, {-1.1, 1.1}}
  ]
 ]

Now you can create three such sliders. Remember whatever you need changed must be wrapped in a Dynamic block.

More advanced functionality is available through Manipulate for which you need to read the docs.