Cumulative count; each successive element of the output is the cumulative count from the initial element, ignoring NAs.
Cumulative max; each successive element of the output is the cumulative max from the initial element, ignoring NAs.
Cumulative min; each successive element of the output is the cumulative min from the initial element, ignoring NAs.
Cumulative product; each successive element of the output is the cumulative product from the initial element, ignoring NAs.
Cumulative sum; each successive element of the output is the cumulative sum from the initial element, ignoring NAs.
Expanding statistical methods made available on numeric Vec objects via enrichment. These methods scan over the Vec and compute cumulative values.