Re: Extract Integers

*To*: mathgroup at smc.vnet.net*Subject*: [mg131427] Re: Extract Integers*From*: Ray Koopman <koopman at sfu.ca>*Date*: Sun, 21 Jul 2013 21:41:37 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net

This avoids having to specify all the non-Rational heads. Also, I have changed -> to :> for safety's sake. Cases[ Replace[ equ, {Rational[a_,b_]:>{a,b}, _[c__]:>{c}}, {0,Infinity}], _Integer, -1] {1, 1, 2, 2, 1, 6, 3, 1, 24, 4, 1, 120, 5} ----- Dana DeLouis <dana01 at icloud.com> wrote: > Hi. I've run out of ideas. Does anyone know the proper way to > extract all the integers from the following simplified version > of a larger problem I'm working on? > > equ=Series[Exp[x],{x,0,5}] //Normal > > 1+x+x^2/2+x^3/6+x^4/24+x^5/120 > > When trying to extract all the integers, > I understand numbers like 120 are part of Rational[1,120] > > equ //FullForm > > << Not shown here >> > > I thought looking at all LevelSpec was the solution, but apparently not. > > Cases[equ, _Integer, Infinity] > {1,2,3,4,5} > > (* Or *) > > Position[equ, _Integer, Infinity] > {{1},{3,2,2},{4,2,2},{5,2,2},{6,2,2}} > > Extract[equ, %] > {1,2,3,4,5} > > Both ways extract from the numerator, but I just can't seem to extract > the {2,6,24,120} inside the denominator. > Does anyone know the proper way? > Thanks in advance. :>~ > > Dana > Mac & Math 9