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Re: Finding extra digit

• To: mathgroup at smc.vnet.net
• Subject: [mg54033] Re: Finding extra digit
• From: "Steve Luttrell" <steve_usenet at _removemefirst_luttrell.org.uk>
• Date: Tue, 8 Feb 2005 05:31:11 -0500 (EST)
• References: <cu78mn$m7l$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

"Bill Rowe" <readnewsciv at earthlink.net> wrote in message 
news:cu78mn$m7l$1 at smc.vnet.net...
> On 2/6/05 at 12:44 AM, steve_usenet at _removemefirst_luttrell.org.uk
> (Steve Luttrell) wrote:
>
>>This example does the sort of thing you want:
>
>>Define a couple if integers differing by one digit.
>>In[1]:={n1,n2}={1234567,1234568};
>
>>Split the integers into their component digits. In[2]:=
>>{d1,d2}=Map[IntegerDigits,{n1,n2}] Out[2]=
>>{{1,2,3,4,5,6,7},{1,2,3,4,5,6,8}}
>
>>Find the digits the integers have in common In[3]:=
>>i=Intersection[d1,d2] Out[3]= {1,2,3,4,5,6}
>
>>Find which digits of n2 do NOT lie in the above common set. In[4]:=
>>Complement[d2,i] Out[4]= {8}
>
> This will not work in general. For example, condider n1 = 811 and n2 =818. 
> The two integers differ by one digit. But since both are composed from the 
> same digits, there are no unique digits in either number.
> --
> To reply via email subtract one hundred and four
>

Agreed. I am not doing a digit by digit comparison as I should have done. In 
effect I have shattered the two numbers into their component digits before I 
start, and then I am comparing these two sets.

Steve Luttrell