seqAgg: Sequential Aggregation

In rBatt/trawlDiversity: Long-term changes in species richness along the North American coastline

Description

Sequentially aggregate columns in a data.table, varying the function and 'by' values

Usage

seqAgg(X, val, FUN, by, ...)

Arguments

X	a data.table
val	character vector indicating columns in X that should be sequuentially aggregated
FUN	a list of functions
by	a list of character vectors; should be of same length as FUN
...	arguments to be passed to each element of FUN

Details

The lengths of FUN and by should be of the same length, but the length of val is independent.

Useful when a summary statistic needs to be computed sequentially (possibly taking the mean over some dimensions before computing the standard deviation, e.g.)

Examples

neus_dat <- data_all[reg=="neus"&year==2010]
a1 <- c("K","stratum")
a2 <- c("stratum")
a3 <- c("")
a_list <- list(a1, a2, a3)
f_list <- list(mean, mean, sd)

neus_dat[,sd(btemp,na.rm=TRUE)] # naive
seqAgg(neus_dat, val="btemp", FUN=f_list, by=a_list, na.rm=TRUE) # sequential
seqAgg(neus_dat, val=c("btemp","depth"), FUN=f_list, by=a_list, na.rm=TRUE) # 2 columns

rBatt/trawlDiversity documentation built on Aug. 14, 2021, 1:01 p.m.