Re: Converting a mapping into a well-defined function

*To*: mathgroup at smc.vnet.net*Subject*: [mg56525] Re: [mg56499] Converting a mapping into a well-defined function*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Thu, 28 Apr 2005 02:40:12 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

Your example output appears to violate your prohibition against sorting the result. A={{a,5},{b,27},{a,14},{c,4},{e,94},{b,6},{d,9},{e,4}}; B=A//. {s___,{x_,y_},m___,{x_,_},f___}:> {s,{x,y},m,f} {{a, 5}, {b, 27}, {c, 4}, {e, 94}, {d, 9}} Bob Hanlon > > From: "Gilmar" <gilmar.rodriguez at nwfwmd.state.fl.us> To: mathgroup at smc.vnet.net > Date: 2005/04/26 Tue PM 09:53:32 EDT > To: mathgroup at smc.vnet.net > Subject: [mg56525] [mg56499] Converting a mapping into a well-defined function > > Dear Mathematica User Friends: > > I need to build a module that takes a non-empty set A > (whose elements are 2-tuples), and appends (or not) those 2-tuples > to a set B according to the following criteria: > > (1.) if the abscissa of a 2-tuple in A is unique (among the abscissas > of all the other 2-tuples in A), then the module appends that 2-tuple > to the set B. > > (2.) if there are n 2-tuples in A that share the same abscissa, then > the module appends the first of those 2-tuples to B ("first" here means > the first of such n 2-tuple encountered, as you read A from left to > right),but does not append the rest to B. > > (3.) the module does not attempt to sort the set B, after the appending > process is completed. > > Example: > > If A = {{a,5},{b,27},{a,14},{c,4},{e,94},{b,6},{d,9},{e,4}} > > then > > B=Module[A]={{a,5},{b,27},{c,4},{d,9},{e,94}}. > > Another way to re-phrase the above example; > > if A defines a mapping: > > A(a)=5, A(b)=27, A(a)=14, A(c)=4, A(e)=94, A(b)=6, A(d)=9, A(e)=4 > > them the module converts the mapping A into a well-defined function: > > A(a)=5, A(b)=27, A(c)=4, A(d)=9, A(e)=94. > > Thank you for your help! > >