regroup: Regroup a dataframe.

In caroline: A Collection of Database, Data Structure, Visualization, and Utility Functions for R

Regroup a dataframe.

Description

Used to group a dataframe of numbers by a factor that need not be the same length. Find the a factor in the old df and use it to group by the new trumping factor (NA's allowed)

Usage

regroup(df, old, new, clmns, funcs=rep('sum',length(clmns)), combine=TRUE)

Arguments

df	a dataframe.
old	the ids to match the rows in df to the 'new' grouping ids.
new	the new ids (must be a vector of the same length as 'old'.
clmns	the colums to include in the output.
funcs	the functions to perform on the output (default is to sum) .
combine	Determines wether to combine with existing groupings or to start fresh.

Value

a dataframe with number of rows equal to the number of factor levels in 'new'

Examples

df <- data.frame(a=rnorm(20),b=rpois(20,1))

mapping <- data.frame(old=rownames(df), new=rep(c('a','b'),10))
regroup(df, old=mapping$old, new=mapping$new)

caroline documentation built on Oct. 21, 2024, 9:06 a.m.