TI-Nspire CX - Splitting a string

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TI-Nspire CX - Splitting a string

Svetroid (guest) 29 Sep 2015 23:58

I was wondering if there was a way to split a string on the TI-Nspire CX. What I want to do specifically is calculate the molar mass of a compound given that compound.
The issue I'm running into is figuring out how to split something like "NaCl" into "Na" and "Cl" in order to find the lookup values separately. Order is important as well, since a compound such as H2O will have the 2 associated with hydrogen, and not oxygen. I'm also not entirely sure when to tell the calculator to stop, as everything is in lowercase due to inputs to a function are forced to lowercase, so it seems like it would be very easy for the calculator to confuse "NaCl" for "N" and "Ac" and "Cl" or something similar.

Svetroid (guest) 30 Sep 2015 00:29

Well, I just figured out how to use mid( and inString( to extract what I want from a string, but the issue is knowing how long the string I want to extract is.

Trenly 30 Sep 2015 03:45

I have a program that balances equations, perhaps you might be able to use a snippet of that? Or just use a periodic table app, and calculate it. But it was written for the 83/84 series

Last edited on 30 Sep 2015 03:46 by Trenly Show more

Svetroid (guest) 30 Sep 2015 11:17

That might be useful. There's no point in using a periodic table app, because I already have my own set up and ready to go. This issue I'm having now is that for something like NaCl, using inString( and mid( will return C, N, Na, Cl, and Ac, and I'm not sure if there's a way to tell the calculator what to specifically look for beforehand, or even if the method I'm using is completely wrong.

Trenly 30 Sep 2015 16:52

http://tibasicdev.wikidot.com/archive:science:chemistry-and-physics

the part you will want is somewhere in there. under Chemistry\more\Eq Balancer

Input "Eq:",Str8
[[0->[E]
DelVar ADelVar B{0->EE
Str8+"+->Str8
inString(Ans,"=->C
DelVar U1->S
Repeat U=length(Str8
    inString(Str8,"+",S->U
    If Ans>C and S<C
    C->U
    sub(Str8,S,U-S->Str0
    {0->A
    Ans->E
    DelVar NDelVar VDelVar WDelVar X0->Z
    For(T,1,length(Str0
        sub(Str0,T,1->Str9
        If X
        Then
            inString("ieaouglrcnsbhdftypmkjqvmxz",Str9->Y
            Z+1->Z
            1-2(X>=30->|LA(Z
            30Y+min(27,X->|LE(Z
        End
        If XY
        Then
            0->X
            Else
            inString("HCONBDAPSFGIKLMRTUVXYZWEJQ~-[e]plotcross*",Str9->X
        End
        If Ans
        Then
            If N
            Then
                For(theta,(W!=0)V+Znot(W),Z
                    N|LA(theta->|LA(theta
                End
                0->N
            End
            If W
            Then
                DelVar WDelVar V
            End
            Else
            inString("0123456789",Str9
            If Ans
            Then
                10N+Ans-1->N
                Else
                If N
                Then
                    For(theta,(W!=0)V+Znot(W),Z
                        N|LA(theta->|LA(theta
                    End
                    0->N
                End
                If W
                Then
                    DelVar VDelVar W
                    Else
                    If V
                    Then
                        Str9=")->W
                        Else
                        (Z+1)(Str9="(->V
                    End
                End
            End
        End
    End
    If X
    Then
        1-2(X>=30->|LA(Z+1
        min(27,X->|LE(Z+1
        Else
        If N
        Then
            For(theta,(W!=0)V+Znot(W),Z
                N|LA(theta->|LA(theta
            End
        End
    End
    1-2(U>C->X
    B+1->B
    {max(1,A),B->dim([E]
    For(theta,1,dim(|LE
        If A
        Then
            sum(cumSum(|LEE=|LE(theta
            If Ans
            Then
                A+1-Ans
                [E](Ans,B)+X|LA(theta->[E](Ans,B
                Else
                A+1->A
                |LE(theta->|LEE(A
                {A,B->dim([E]
                X|LA(theta->[E](A,B
            End
            Else
            |LE(1->|LEE(1
            X|LA(1->[E](1,B
            1->A
        End
    End
    U+1->S
End
A+1->A
max(A,B+1->X
{A,X->dim([E]
1->[E](A,1
1->[E](A,X
Matr>list(rref([E]),X,|LA
B->dim(|LA
cumSum(1+0|LA)not(not(fPart(|LA->E
SortD(|LE
sum(not(not(|LE->dim(|LE
For(theta,1,Ans
    |LA(|LE(theta
    If fPart(Ans
    Then
        {1,abs(Ans
        Repeat |E~9>Ans(2
            Ans(2){1,fPart(Ans(1)/Ans(2
        End
        |LAround(Ans(1)^^-1,0->A
    End
End
Disp |LA

Code obtained through Cemetechs Source Coder.
Again, this was written for the Ti-83+/84 family. It gives the balancing numbers.
Given the input

C8H18+O2=CO2+H20

it will return:

{2 25 16 18}