Re: count zeros in a number
- To: mathgroup at smc.vnet.net
- Subject: [mg121806] Re: count zeros in a number
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Mon, 3 Oct 2011 04:22:16 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
On 10/2/11 at 2:36 AM, dimmechan at yahoo.com (dimitris) wrote: >Consider e.g. the number 24^24*55^55. This number ends with exactly >55 zeros as the following demonstrate >In[201]:= Mod[24^24*55^55, 10^55] Mod[24^24*55^55, 10^56] >Out[201]= 0 Out[202]= >20000000000000000000000000000000000000000000000000000000 >What I want now is a way to count the zeros that a number ends >without knowing in advance this number of zeros like in the above >example. Here are a couple of ways: In[10]:= Count[IntegerDigits[Mod[24^24*55^55, 10^56]], 0] Out[10]= 55 In[11]:= Length[Split[IntegerDigits[Mod[24^24*55^55, 10^56]]][[-1]]] Out[11]= 55 The first method assumes the only zeros are trailing zeros. The second does not make this assumption by does assume there are trailing zeros.