Re: FindROot and substitutions
- To: mathgroup at smc.vnet.net
- Subject: [mg89977] Re: FindROot and substitutions
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Wed, 25 Jun 2008 06:30:36 -0400 (EDT)
On 6/24/08 at 3:20 AM, jeanmarc.gulliet at gmail.com (Jean-Marc Gulliet) wrote regarding: >>>g := x z; >> >>----------^ You used a semicolon here, so I suppose that you do not >>understand the difference between SetDelayed and Set. >The above expression is not a compound expression. But it is a compound expression. Specifically, it is the compound expression g := x z;Null which is clearly shown by In:= FullForm@Hold[g := x z;] Out//FullForm= \ Hold[CompoundExpression[SetDelayed[g,Times[x,z]],Null]] >SetDelayed does not produce any output. >Therefore the semicolon is not needed and does not change anything. >So someone may infer that you do not have a clear idea about about >the differences between immediate and delayed assignments, which are >topics of some importance to answer the rest of your original >question. Further, there is the only the symbol g appears on the left hand side of the SetDelayed. I cannot think of any reason why Set would not be preferred here, adding to the impression there is a lack of understanding of the differences between Set and SetDelayed.