In shabbychef/zipper: Zip Sorted Arrays Together

# set the knitr options ... for everyone!
# if you unset this, then vignette build bonks. oh, joy.
#opts_knit$set(progress=TRUE)
opts_knit$set(eval.after='fig.cap')
# for a package vignette, you do want to echo.
# opts_chunk$set(echo=FALSE,warning=FALSE,message=FALSE)
opts_chunk$set(warning=FALSE,message=FALSE)
#opts_chunk$set(results="asis")
opts_chunk$set(cache=TRUE,cache.path="cache/")

#opts_chunk$set(fig.path="figure/",dev=c("pdf","cairo_ps"))
opts_chunk$set(fig.path="tools/figure/",dev=c("png"))
opts_chunk$set(fig.width=7,fig.height=6,dpi=100,out.width='700px',out.height='600px')

# doing this means that png files are made of figures;
# the savings is small, and it looks like shit:
#opts_chunk$set(fig.path="figure/",dev=c("png","pdf","cairo_ps"))
#opts_chunk$set(fig.width=4,fig.height=4)
# for figures? this is sweave-specific?
#opts_knit$set(eps=TRUE)

# this would be for figures:
#opts_chunk$set(out.width='.8\\textwidth')
# for text wrapping:
options(width=96,digits=2)
opts_chunk$set(size="small")
opts_chunk$set(tidy=TRUE,tidy.opts=list(width.cutoff=50,keep.blank.line=TRUE))
library(ggplot2)
library(zipper)
library(dplyr)
library(moments)
library(microbenchmark)
# chicken and egg dept:
# [![CRAN](http://www.r-pkg.org/badges/version/zipper)](http://cran.rstudio.com/package=zipper) 
# [![Downloads](http://cranlogs.r-pkg.org/badges/zipper?color=brightgreen)](http://www.r-pkg.org/pkg/zipper)
# [![Total](http://cranlogs.r-pkg.org/badges/grand-total/zipper?color=brightgreen)](http://www.r-pkg.org/pkg/zipper)
#[![CRAN](http://www.r-pkg.org/badges/version/zipper)](https://cran.r-project.org/package=zipper)
#[![Downloads](http://cranlogs.r-pkg.org/badges/zipper?color=green)](http://www.r-pkg.org/pkg/zipper)
#[![Total](http://cranlogs.r-pkg.org/badges/grand-total/zipper?color=green)](http://www.r-pkg.org/pkg/zipper)

zipper

it zips the index in the basket!

Zips two sorted arrays into each other. That's it. Not for CRAN.

-- Steven E. Pav, [e-mail]

Installation

This package can be installed via drat, or from github:

# via drat:
if (require(drat)) {
    drat:::add("shabbychef")
    install.packages("zipper")
}
# get snapshot from github (may be buggy)
if (require(devtools)) {
    install_github('shabbychef/zipper')
}

What?

Suppose you have two sorted arrays and need to align them. That's a zip operation. Back when I worked with time series (in Matlab), a zip operation was at the base of the 'look back' join operation. That is all this package does:

require(zipper)
set.seed(1234)
reference_x <- sort(rnorm(10000))
lookup_y <- sort(rnorm(100))
idxs <- zipper::zip_le(reference_x,lookup_y)
head(idxs)

# compare to this slow version:
altv <- rep(NA_integer_,length(lookup_y))
for (iii in seq_along(lookup_y)) {
    altv[iii] <- sum(reference_x <= lookup_y[iii])
}
stopifnot(all.equal(altv,idxs))

shabbychef/zipper documentation built on April 5, 2021, 7:31 p.m.