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Re: rule based program for "Deleting repeated members of a list."


Jean-Marc Gulliet wrote:
> I was wandering why you used b and d as pattern name with a condition on 
> them rather than b and c, but I realized that when using c as pattern 
> name in place of d the replacement fails.
> 
> In[1]:= s = {a, b, c, c, d, e, e, f, g, g, g, h, a, b};

Hi,

You probably noticed this by now, but on the following line there should 
be {a,b,d} instead of {a,b,d}

> s //. {a___, b_, c_, d___} :> {a, b, c} /; b == c

---------------------------------------^

s //. {a___, b_, c_, d___} :> {a, b, d} /. b === c

> s //. {a___, b_, d_, e___} :> {a, b, e} /; b == d
> 
> Out[2]= {a, b, c, c}
> 
> Out[3]= {a, b, c, d, e, f, g, h, a, b}
> 
> Does anyone know why?
> 

-- 
Szabolcs


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