Re: importing data from Excel to Mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg85723] Re: importing data from Excel to Mathematica*From*: "Steve Luttrell" <steve at _removemefirst_luttrell.org.uk>*Date*: Wed, 20 Feb 2008 06:55:43 -0500 (EST)*References*: <fpe06j$ser$1@smc.vnet.net>

I assume you can import your equation string into Mathematica in the form "x1 = A x2 + B y1\ny1 = C y2 - D x1" where \n is the newline character. In[1]:= s="x1 = A x2 + B y1\ny1 = C y2 - D x1" Out[1]= x1 = A x2 + B y1 y1 = C y2 - D x1 The aim now is to manipulate this into the correct form for an algebraic expression that Mathematica can work with. Split the above single string into two separate strings. In[2]:= s2=StringSplit[s,"\n"] Out[2]= {x1 = A x2 + B y1,y1 = C y2 - D x1} Replace = (i.e. Set) with == (i.e. Equal) to make the strings have the correct Mathematica syntax for equations. In[3]:= s3=StringReplace[s2,"="->"=="] Out[3]= {x1 == A x2 + B y1,y1 == C y2 - D x1} Convert the strings to algebraic expressions that Mathematica can manipulate symbolically. In[4]:= e=ToExpression[s3] Out[4]= {x1==A x2+B y1,y1==-D x1+C y2} Solve the equations. In[5]:= Solve[e,{x1,y1}] Out[5]= {{x1->-((-A x2-B C y2)/(1+B D)),y1->-((A D x2-C y2)/(1+B D))}} Stephen Luttrell West Malvern. UK "Tugrul Temel" <temelt at xs4all.nl> wrote in message news:fpe06j$ser$1 at smc.vnet.net... > Dear All, > > I have an Excel database with strings of equations in the following form: > > x1 = A x2 + B y1 > y1 = C y2 - D x1 > > I like to import these equations to Mathematica and solve for x1 and y1: > > Which format is the best for importing? > > Thanks > > Tugrul > > > > > >