[R] Adding a line to barchart

[PIKAL Petr]

Hi
This function adds line to each panel

addLine <- function (a = NULL, b = NULL, v = NULL, h = NULL, ..., once = F) 
{
    tcL <- trellis.currentLayout()
    k <- 0
    for (i in 1:nrow(tcL)) for (j in 1:ncol(tcL)) if (tcL[i, 
        j] > 0) {
        k <- k + 1
        trellis.focus("panel", j, i, highlight = FALSE)
        if (once) 
            panel.abline(a = a[k], b = b[k], v = v[k], h = h[k], 
                ...)
        else panel.abline(a = a, b = b, v = v, h = h, ...)
        trellis.unfocus()
    }
  }


addLine(v=2, col=2, lty=3)

Petr

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Jonathan Greenberg
> Sent: Tuesday, January 22, 2013 11:42 PM
> To: r-help
> Subject: [R] Adding a line to barchart
> 
> R-helpers:
> 
> I need a quick help with the following graph (I'm a lattice newbie):
> 
> require("lattice")
> npp=1:5
> names(npp)=c("A","B","C","D","E")
> barchart(npp,origin=0,box.width=1)
> 
> # What I want to do, is add a single vertical line positioned at x = 2
> that lays over the bars (say, using a dotted line).  How do I go about
> doing this?
> 
> --j
> 
> --
> Jonathan A. Greenberg, PhD
> Assistant Professor
> Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
> Department of Geography and Geographic Information Science University
> of Illinois at Urbana-Champaign
> 607 South Mathews Avenue, MC 150
> Urbana, IL 61801
> Phone: 217-300-1924
> http://www.geog.illinois.edu/~jgrn/
> AIM: jgrn307, MSN: jgrn307 at hotmail.com, Gchat: jgrn307, Skype: jgrn3007
> 
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> 
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