sum                   package:base                   R Documentation

Sum of Vector Elements

Description:

     'sum' returns the sum of all the values present in its arguments.

Usage:

     sum(..., na.rm = FALSE)

Arguments:

     ...: numeric or complex or logical vectors.

   na.rm: logical.  Should missing values be removed?

Details:

     This is a generic function: methods can be defined for it directly
     or via the 'Summary' group generic. For this to work properly, the
     arguments '...' should be unnamed, and dispatch is on the first
     argument.

     If 'na.rm' is 'FALSE' an 'NA' value in any of the arguments will
     cause a value of 'NA' to be returned, otherwise 'NA' values are
     ignored.

     Logical true values are regarded as one, false values as zero. For
     historical reasons, 'NULL' is accepted and treated as if it were
     'integer(0)'.

Value:

     The sum. If all of '...' are of type integer or logical, then the
     sum is integer, and in that case the result will be 'NA' (with a
     warning) if integer overflow occurs.  Otherwise it is a length-one
     numeric or complex vector.

     *NB:* the sum of an empty set is zero, by definition.

S4 methods:

     This is part of the S4 'Summary' group generic.  Methods for it
     must use the signature 'x, ..., na.rm'.

     'plotmath' for the use of 'sum' in plot annotation.

References:

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

See Also:

     'colSums' for row and column sums.

