Re: Polynomial to List

*To*: mathgroup at smc.vnet.net*Subject*: [mg76952] Re: [mg76897] Polynomial to List*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Wed, 30 May 2007 05:32:35 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200705290907.FAA04110@smc.vnet.net>*Reply-to*: murray at math.umass.edu

First, let's make the problem a bit more complicated by looking at, say, the polynomial: p = c + k x - 7 x^2 + x^3 + Pi x^4 Now how does Mathematica parse that? Use FullForm: FullForm[p] Plus[c,Times[k,x],Times[-7,Power[x,2]],Power[x,3],Times[Pi,Power[x,4]]] Thus the structure is Plus[...] where the argument of Plus is a sequence of the various terms. You want a list consisting of these terms, so a way to do it is to change Plus to List. The Apply function does this: Apply[List,p] {c, k*x, -7*x^2, x^3, Pi*x^4} (There, and below, I show the linear, 1-dimensional InputForm of the 2D standard form in which Mathematica would display the output.) Finally, if you want to save some punctuation, use the @@ input form for Apply, like this: List@@p {c, k*x, -7*x^2, x^3, Pi*x^4} Finally, reverse the order of the terms by using -- what else? -- Reverse: Reverse[List@@p] {Pi*x^4, x^3, -7*x^2, k*x, c} Nick Hoffman wrote: > I have a polynomial, > Lets say: > > 1 + x + x^2 + x^3 + x^4 > > > and all I need to do is get that into a list of this form > > {x^4, x^3, x^2, x, 1} > > Any help would be greatly appreciated! Thanks! > > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**Polynomial to List***From:*"Nick Hoffman" <hoffmannick@gmail.com>