data.table (version 1.18.2.1)

fctr: Create a factor retaining original ordering

Description

Creates a factor.

By default, the output will have its levels in the original order, i.e., levels = unique(x), as opposed to factor's default where levels = sort(unique(x)).

Usage

fctr(x, levels=unique(x), ..., sort=FALSE, rev=FALSE)

Value

Factor vector having levels ordered according to the order of elements in input and arguments sort, rev.

Arguments

x

Object to be turned into a factor.

levels

Levels for the new factor; unique(x) by default.

...

Other arguments passed to factor.

sort

Logical, default FALSE. Should levels be sorted?

rev

Logical, default FALSE. Should levels be reversed? Applied after sort.

Examples

levels(factor(c("b","a","c")))
levels(fctr(c("b","a","c")))
levels(fctr(c("b","a","c"), rev=TRUE))
levels(fctr(c("b","a","c"), sort=TRUE))
levels(fctr(c("b","a","c"), sort=TRUE, rev=TRUE))