sum returns the sum of all the values
present in its arguments.
sum(..., na.rm = FALSE)NaN) be
removed?... 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.
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 or NaN value in
any of the arguments will cause a value of NA or NaN to
be returned, otherwise NA and NaN 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).
Loss of accuracy can occur when summing values of different signs: this can even occur for sufficiently long integer inputs if the partial sums would cause integer overflow. Where possible extended-precision accumulators are used, but this is platform-dependent.
colSums for row and column sums.