# I need help just to get going

I’m sorry to be thick, but I’m new to CL and confused by the basics.

I programme in Lua, but CL is, as I say, confusing.

To get me going could some kind person just talk be through how I get and set a variable that I use in my graph, say E, and use that to set the graph bounds.

I can use bounds like this:

bounds:

makeBounds(-300,400,-300,300)

But can’t work out how to use the E variable from the graph in makeBounds.

Sorry for being thick on this basic stuff.

Cheers

Garry

Variables exist in the graph and separately in the CL, so you can do it in two ways.

1. Directly into the bounds
``````bounds: makeBounds(this.number(`E`), 400,-300,300)
``````
1. Create a variable in the CL first
``````xmin=this.number(`E`)
bounds: makeBounds(xmin,400,-300,300)
``````

If you want E to effect more than one of the bounds, I suggest doing those calculations in the graph as calculations in CL are a little more unwieldy.

Also, I’m using `this` to refer to the current component, but you can replace that with another component name perhaps from another slide.

You can also refer to numbers in a list by referring to it’s index in the list:
`this.number(`L[3]`)` would pull the third element in list L.

Daniel

Many, many thanks

I felt such an idiot to ask, but could find no insight in the ‘user manual’.

Cheers

Garry

Daniel

One more question (I hope), I get a warning that says This data come from a full size screen graph - dependencies…

Not sure what this means?

Can you throw some light on the warning?

I think that’s a common error with full-screen graphs. I’m not entirely sure, but I think it’s because there’s the possibility of students adding (or removing) an expression that could “break” your code. For example, if a student added E=5 into the graph, desmos wouldn’t know which E to use for your bounds.

Daniel

Thanks for the insight. In my use case I’ll be ok and it’s only a warning.

But at least I appreciate what it means.

Cheers

Garry