Converting a mapping into a well-defined function

*To*: mathgroup at smc.vnet.net*Subject*: [mg56499] Converting a mapping into a well-defined function*From*: "Gilmar" <gilmar.rodriguez at nwfwmd.state.fl.us>*Date*: Tue, 26 Apr 2005 21:53:32 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

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!

**Follow-Ups**:**Re: Converting a mapping into a well-defined function***From:*János <janos.lobb@yale.edu>

**Re: Converting a mapping into a well-defined function***From:*Sseziwa Mukasa <mukasa@jeol.com>