Re: Dont Understand

*To*: mathgroup at smc.vnet.net*Subject*: [mg15936] Re: [mg15857] Dont Understand*From*: "Tomas Garza" <tgarza at mail.internet.com.mx>*Date*: Wed, 17 Feb 1999 23:34:03 -0500*Sender*: owner-wri-mathgroup at wolfram.com

Don McKenzie Paul wrote: >I'm not an expert in Mathematica and would appreciate comments on why >init1 returns a list with all zeros replaced by -1, but init does not. >Its probably very simple but its confused me. >Don >init[n_Integer]:=Module[ {s=Table[Random[Integer],{n n}]}, s/.{0->-1}; Partition[s,n] ] >init1[n_Integer]:=Module[ {s=Table[Random[Integer],{n n}]}, s/.{0->-1} ] Don, In init you use a transformation rule on s, but never assign the result to something. Hence the Partition is applied to the original s. Try something like init[n_Integer]:=Module[ {s=Table[Random[Integer],{n n}]}, z=s/.{0->-1}; Partition[z,n] ] However, in init1 you perform the transformation without a semicolon at the end, hence the result is simply displayed on the screen -- you can do nothing with it until you assign it to a symbol. Good luck, Tomas Garza Mexico City