Creating a Piecewise function with imported list of arbitrary length

*To*: mathgroup at smc.vnet.net*Subject*: [mg128927] Creating a Piecewise function with imported list of arbitrary length*From*: Nick Broderick <crazychessman at msn.com>*Date*: Tue, 4 Dec 2012 04:13:30 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net

Apologies if this seems like a simple question, but I'm not familiar enough with Mathematica syntax to know how to do this. Essentially I have an arbitrary list (length n) of pairs -- taken from an input file -- from which I need to define a Piecewise function. The pairs (x_i,y_i) define the left-sided endpoints for each portion of the function, and the last point defines the value y_n of the function for x > x_n. For example: {{0,1},{300,2},{600,3}} defines a Piecewise function: f(x)= {{1, 0 <= x <300},{2, 300 <= x <600}, {3, x > 600}, {0, True}} But I'm not sure how to go about creating a arbitrary list of conditions fr= om my list of pairs. Any help would be appreciated.

**Follow-Ups**:**Re: Creating a Piecewise function with imported list of***From:*Bob Hanlon <hanlonr357@gmail.com>