B4J Question Evaluating a math expression given in string, HELP??

[ilan]

hi

i would like to make a math calculation from a given string like:

dim mathproblem as string = "(25*2)-4"
log(mathproblem)

and i should get = 46

i found a great VB source that is really working very well but i dont know how to convert "redim" and "redim preserve" to b4x language

i will attach the b4j project (vb code is inside)

can someone make a working b4x code from it??

thanx

 

[Roycefer]

Have you looked at the ExpressionEvaluator and B4X Evaluator libraries? https://www.b4x.com/android/forum/threads/class-b4x-eval-expressions-evaluator.54629/#content

 

[ilan]

Have you looked at the ExpressionEvaluator and B4X Evaluator libraries? https://www.b4x.com/android/forum/threads/class-b4x-eval-expressions-evaluator.54629/#content

no i have not...

2 days i am struggling with it

thank you very much @Roycefer

 

[MaFu]

You can also use MF_MathParser which is part of my jMFLib.

 

[Daestrum]

You could also use my Nashorn library
define a js function like

function evaluate(a,b){
    return new java.lang[b](eval(a))
}

This also allows you to specify the data type for the return
so you call it by

   script.invoke("evaluate",Array("Math.sqrt(12*(14-6)/7)","Float"))

And in this case it will return a float value.
(You can use Double,Float,Integer,String etc)

 

[ilan]

You could also use my Nashorn library
define a js function like

function evaluate(a,b){
    return new java.lang[b](eval(a))
}

This also allows you to specify the data type for the return
so you call it by

   script.invoke("evaluate",Array("Math.sqrt(12*(14-6)/7)","Float"))

And in this case it will return a float value.
(You can use Double,Float,Integer,String etc)

thanks @Daestrum, but the class of erel is exactly what i needed because i am developing a b4i tool and his class runs on all b4x products.
i use his class also with b4j where i build some assisting tools for my new app.