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Pattern example

• To: mathgroup at smc.vnet.net
• Subject: [mg19284] Pattern example
• From: senisen at ptty.loxinfo.co.th (chris)
• Date: Sat, 14 Aug 1999 01:45:11 -0400
• Organization: My Org
• Sender: owner-wri-mathgroup at wolfram.com

I am trying to learn how to use patterns and replacements,
for instance this example:

{{1+a},{2+a},{3+a}}  /.  {t_+a}->c
 {c,c,c}

FullForm[{{1+a},{2+a},{3+a}}  /.  {t_+a}->c]
FullForm= List[c,c,c]

So far so good

Then
{{1+a},{2+a},{3+a}}  /.  t_->c
c  
 this is no more a list, but

FullForm[{{1+a},{2+a},{3+a}}  /.  {t_}->c]
List[c,c,c]   
shows it as a list

What is behind this difference?

Chris

• Follow-Ups:
  • Re: Pattern example
    • From: "Kevin J. McCann" <kevinmccann@Home.com>