Re: Quick Mathematica Question

*To*: mathgroup at smc.vnet.net*Subject*: [mg115293] Re: Quick Mathematica Question*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Thu, 6 Jan 2011 02:07:40 -0500 (EST)

It's unclear exactly what types of objects you want here: strings consisting of "0" and "1"; actual lists of digits 0 and 1; or integers whose digits are 0 and 1. If strings, the following will do what you want: stringstep[str_] := StringReplace[str, {"0" -> "1", "1" -> "10"}] NestList[stringstep, "0", 8] If lists of binary digits: bitstep[lis_] := Flatten@Replace[lis, {0 -> 1, 1 -> {1, 0}}, 1] NestList[bitstep, {0}, 8] If integers with digits 0 and 1, you could start with either of the above and then just convert the strings or binary lists into integers. Thus if you assign the last output to, say, bitList, then: FromDigits /@ bitList If you want your results to be displayed, as you showed, on separate lines, then just use ColumnForm on your output. On 1/5/2011 5:46 AM, Dean wrote: > How would I program user-defined rules such as > > 0->1 > 1->10 > > to give the output, and specify the number of recursions. For example, > starting with 0, > > 0 > 1 > 10 > 101 > 10110 > ... > > Specified, 5 generations. -- 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