Element Extraction

*To*: mathgroup at smc.vnet.net*Subject*: [mg19240] Element Extraction*From*: kewjoi at hixnet.co.za (Kew Joinery)*Date*: Wed, 11 Aug 1999 02:06:52 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Hello everyone, I have a problem extracting list of list. Given some list, consisting of elements (not all of them distinct) with the same length and some target list of the same length, for example: In[26]:= someList={{0,0,0},{0,0,1},{0,0,2},{0,1,0},{0,1,1},{0,1,2},{0,2,0},{0,2,1},{0, 2,2},{1,0,0},{1,0,1},{1,0,2},{1,1,0},{1,1,1},{1,1,2},{1,2,0},{1,2,1},{1, 2,2},{2,0,0},{2,0,1},{2,0,2},{2,1,0},{2,1,1},{2,1,2},{2,2,0},{2,2,1},{2, 2,2}}; In[27]:= target={0,0,1}; Hamming distance between two bit strings means the number of bit positions in which they differ. For example consecutive elements of the Gray code list have Hamming distance = 1. I need to extract these cases(elements of someList) which differ from target in one coordinate (Hamming distance = 1) or less (the element===target itself//Hamming distance=0), so the answer should be: In[33]:= answer={{0,0,0},{0,0,1},{0,0,2},{0,1,1},{0,2,1},{1,0,1},{2,0,1}}; How could I achieve the extraction efficiently? Thank you in advance for any suggestions. Eugene

**Follow-Ups**:**Re: Element Extraction***From:*"Carl K.Woll" <carlw@fermi.phys.washington.edu>