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for loop question

Ben Bolker 
This is a "gotcha", which I think I will add to my list of "R traps"
(http://www.zoo.ufl.edu/bolker/emd/R/R-traps.html).

  The problem is in "operator precedence", or "priority": the colon
operator has higher precedence than the plus operator, so R treats

i+1:3

as

i+(1:3)

rather than

(i+1):3

(which is what you should write to get the behavior you expected).  I'm
not sure where this is found in the documentation.

OK, p. 14 of the "Introduction to R" says

  The colon operator has highest priority within an expression, so, for
  example 2*1:15 is the vector c(2, 4, ..., 28, 30). Put n <- 10 and
  compare the sequences 1:n-1 and 1:(n-1).
On Tue, 11 Sep 2001, HEUMANN,JOHN (A-Loveland,ex1) wrote:

            

      
      
      
    

        

  
    

      
      
    

  


  


  


  
  

    

  

    
      
    
    
Thread (6 messages)

  

  

    
            
        john_heumann@agilent.com
        
        for loop question
      
      Sep 11
    
    
      
            
        Thomas Lumley
        
        for loop question
      
      Sep 11
    
    
      
            
        Ben Bolker
        
        for loop question
      
      Sep 11
    
    
      
            
        Uwe Ligges
        
        for loop question
      
      Sep 11
    
    
      
            
        Duncan Murdoch
        
        for loop question
      
      Sep 11
    
    
      
            
        Giovanni Petris
        
        for loop question
      
      Sep 11