If loop with a range variable

[ksk_10594232]

Hi

How do I program an if-loop with a range variable, and not a scalar? Is that possible?

[Werner_E]

The "if" statement is a branch, not a loop!

Its unclear to me what you mean and how this would have to do with a range variable.

Maybe you can give a couple of examples of what you are looking for.

If you are looking for multiple branching like the "switch" statement in C - Prime does not provide a comparable statement.

But depending on the specific problem its often possible to find a simpler solution compared to a cascade of if's and elseif's.

[ksk_10594232]

I have attached an example which I hope will clearify my question 🙂

[Werner_E]

And what kind of data structure do you expect as the output?

You have to be aware that ranges are not vectors! Ranges should only be used on three occasions:

To index the elements of a vector or matrix
In a for-loop inside a program
As abscissa values when you plot a function

In all other cases you should use vectors.

Maybe this is what you are looking for:

Prime 9 file attached

[ksk_10594232 · Accepted solution]

I found a solution to get around the problem. Thanks anyways!

[terryhendicott]

Hi,

Here is solution that does not use programmed if statements suitable for Express version of Prime.

Cheers

Terry

[Werner_E]

If you are looking for a version for Express, it would be easier to use the if-function instead of the programmed if-statement once x.test is defined as a vector and not a range.

Or you do completely without any "if" and use the "min" function, which is also available in Prime Express

Using functions has various advantages over manipulating vectors throughout (which is a way of working many are used from using a spreadsheet program).

[ksk_10594232]

Thanks ! 🙂

[ksk_10594232]

How can I use the same approach for an else/if statement as shown in the attached file? 

[Werner_E]

You again turn the calculation into a function and call it vectorized with a vector (not a range!) as argument.

Or are you looking for a function which also works in Prime Express where programming is not available?

The you would use nested if-functions, similar to what you have to do in any spreadsheet program like Calc ode Excel - but this tends to look cluttered and messy:

[ksk_10594232]

I understand, but I don't know how to write the above calculation into a function. 

[ksk_10594232]

My bad, I noticed that to wrote above 😄 Thank you