Re: Extract Integers
- To: mathgroup at smc.vnet.net
- Subject: [mg131435] Re: Extract Integers
- From: Helen Read <readhpr at gmail.com>
- Date: Sun, 21 Jul 2013 21:44:17 -0400 (EDT)
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I'm not completely sure what you are trying to do, but if I understand you correctly, why not simply get the numerators and denominators of the coefficients? coeffs = CoefficientList[equ, x] Numerator[coeffs] Denominator[coeffs] You can delete duplicates if desired. DeleteDuplicates[Numerator[coeffs]] DeleteDuplicates[Denominator[coeffs]] Helen Read University of Vermont On 7/21/2013 4:19 AM, Dana DeLouis 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 > > -- HPR