coalesce {preputils}

select 1st existing value of several columns

Description

Inspired by the respectively named sql function. In a list of vectors with equal length the function for each of the observations selects the first value that is not NA, in the order provided

Usage

coalesce(...)

Arguments

...

vectors holding the values, sepearated by "," (commonly columns of data.frame)

Details

Data are transformed according to

b=\frac{2^M}{2^M+1}

Value

A named vector holding the supplemented values

Examples

    a1 = c(1,NA,NA,NA)
    a2 = c(2,2,NA,NA)
    a3 = c(NA,3,3,NA)
    cbind(a1,a2,a3,suppl=coalesce(a1,a2,a3))