Syntax                 package:base                 R Documentation

Operator Syntax and Precedence

Description:

     Outlines R syntax and gives the precedence of operators

Details:

     The following unary and binary operators are defined.  They are
     listed in precedence groups, from highest to lowest.

       '[ [['             indexing
       ':: :::'           access variables in a name space
       '$ @'              component / slot extraction
       '^'                exponentiation (right to left)
       '- +'              unary minus and plus
       ':'                sequence operator
       '%any%'            special operators
       '* /'              multiply, divide
       '+ -'              (binary) add, subtract
       '< > <= >= == !='  ordering and comparison
       '!'                negation
       '&  &&'            and
       '| ||'             or
       '~'                as in formulae
       '-> ->>'           rightwards assignment
       '='                assignment (right to left)
       '<- <<-'           assignment (right to left)
       '?'                help (unary and binary)

     Within an expression operators of equal precedence are evaluated
     from left to right except where indicated.

     The links in the *See Also* section cover most other aspects of
     the basic syntax.

Note:

     There are substantial precedence differences between R and S.  In
     particular, in S '?' has the same precedence as (binary) '+ -' and
     '& && | ||' have equal precedence.

References:

     Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S
     Language_. Wadsworth & Brooks/Cole.

See Also:

     'Arithmetic', 'Comparison', 'Control', 'Extract', 'Logic',
     'NumericConstants', 'Paren', 'Quotes', 'Reserved'.

     The _R Language Definition_ manual.

