[R] lattice barchart() with two variables

[Bert Gunter]

See inline.

-- Bert



On Wed, Aug 22, 2018 at 9:17 AM Rich Shepard <rshepard using appl-ecosys.com>
wrote:

> On Wed, 22 Aug 2018, Bert Gunter wrote:
>
> > No reproducible example (see posting guide below) so minimal help.
>
> Hi Bert,
>
>    I thought the header and six data rows of the dataframe plus the syntax
> of
> the command I used were sufficient. Regardless, here's the dput() output:
>
> structure(list(Year = c(1989L, 1990L, 1991L, 1993L, 1994L, 1995L,
> 1996L, 1997L, 1998L, 1999L, 2000L, 2001L, 2002L, 2003L, 2004L,
> 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L,
> 2014L, 2015L, 2016L, 2017L, 2018L), Med = c(91.17, 91.22, 91.24,
> 91.14, 93.92, 94.34, 91.32, 91.36, 91.24, 94.33, 94.33, 94, 94.32,
> 94.02, 94.19, 94.05, 94.21, 94.21, 94.32, 94.13, 94.27, 94.34,
> 94.23, 94.25, 94.15, 94.01, 94.09, 94.31, 94.35), Max = c(93.32,
> 93.43, 92.89, 93.02, 95.74, 96.85, 95.86, 94.25, 93.67, 97.42,
> 97.42, 94.99, 96.58, 96.57, 96.32, 95.96, 97.4, 97.28, 96.72,
> 97.43, 95.95, 97.82, 97, 96.6, 96.24, 96.68, 96.96, 96.39, 96.95
> )), class = "data.frame", row.names = c(NA, -29L))
>
>
> > Remove the quotes from your formula. Why did you think they should be
> > there? -- see ?formula.
>
>    A prior attempt seemed to suggest the strings needed to be quoted.
>
> > Read the relevant portions of ?xyplot carefully (again?). You seemed to
> > have missed:
>
>    I'm trying to create a barchart, not an xyplot.
>

Please see ?xyplot, where you will also see dotplot, barchart, etc.
documented !

>
> > y <- runif(5)
> > x <- factor(letters[1:5])
> > barchart(y~x)
>
>    Okay. I see one error in my command that's fixed here:
>
> barchart(stage_heights$Med ~ stage_heights$Year, horizontal=FALSE)
>
> > As for fiddling with the colors and patterns of the bars -- generally a
> bad
> > idea , especially fill patterns, btw -- see the "col" argument of
> > ?panel.barchart, which is always where you should look for such info
> (i.e.
> > panel.whatever). I don't know whether you can fool with fill patterns* --
> > it may depend on your graphics device -- but you can google around or see
> > what trellis.par.get() has available (which can be specified in the
> > "par.settings" argument list in the call).
>
>    I need pairs of bars, one each for Med and Max for each year. Color or
> pattern would distinguish the two.
>

?xyplot tells you about the "groups" argument that does exactly this.
Again, please read the relevant sections of ?xyplot carefully.


> > * For why fooling with fill patterns is a bad idea, google "moiré
> patterns".
>
>    I did not think that a solid fill or striped fill would create a moire
> pattern on either a computer screen viewing a .pdf file or on the printed
> page.
>

I agree. But color alone usually is the better classifier and suffices; in
black and white, light gray vs. black would work as well for just two
categories I think.



>
>    Correcting the barchard() command fixed the main issue; getting the
> second
> set of bars is still eluding me, but I'll continue working on fixing this.
> I'll get the years as the x-axis labels rather than year number in sequence
> from 1 to 29.
>
> Thanks,
>
> Rich
>
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