In R, is it possible to do "conditional color formatting" as is done in Microsoft Excel?
An Image with R vanilla
I had quite some fun constructing an image with additional text() at each cell. Wrapped in an optional local({ .. }) to prevent the environment from getting cluttered.
The approach requires data which can be represented as square matrix!
Note. Was a long day in Germany. Would be nice if someone suggests a simplified approach to rotate M--probably by reverting s somewhere? Thank you!
local({
# own re-format routine
values = unlist(z$name_coun)
row_names = unique(z$year_1)
col_names = unique(z$year_2)
nr = nc = length(row_names)
M = matrix(values, nrow = nr, byrow = TRUE, dimnames = list(row_names, col_names))
# reverting magic that harmonises col-argument of image and text
s = seq(nr)
M = t(M[rev(s), ])
image(s, s, M, xlab='', ylab = '', axes = FALSE,
col = hcl.colors(1e3, 'Reds 3', rev = TRUE))
with(expand.grid(x = s, y = s), text(x, y, labels = M, col = "black"))
# add custome axes
axis(2, at = s, labels = rev(row_names), las = 2, col = NA) # left
axis(3, at = s, labels = col_names, las = 2, col = NA) # top
})

Data
> dput(z)
structure(list(year_1 = c(2000L, 2000L, 2000L, 2000L, 2000L,
2000L, 2000L, 2000L, 2000L, 2000L, 2000L, 2000L, 2000L, 2000L,
2000L, 2000L, 2000L, 2000L, 2000L, 2000L, 2000L, 2001L, 2001L,
2001L, 2001L, 2001L, 2001L, 2001L, 2001L, 2001L, 2001L, 2001L,
2001L, 2001L, 2001L, 2001L, 2001L, 2001L, 2001L, 2001L, 2001L,
2001L, 2002L, 2002L, 2002L, 2002L, 2002L, 2002L, 2002L, 2002L,
2002L, 2002L, 2002L, 2002L, 2002L, 2002L, 2002L, 2002L, 2002L,
2002L, 2002L, 2002L, 2002L, 2003L, 2003L, 2003L, 2003L, 2003L,
2003L, 2003L, 2003L, 2003L, 2003L, 2003L, 2003L, 2003L, 2003L,
2003L, 2003L, 2003L, 2003L, 2003L, 2003L, 2003L, 2004L, 2004L,
2004L, 2004L, 2004L, 2004L, 2004L, 2004L, 2004L, 2004L, 2004L,
2004L, 2004L, 2004L, 2004L, 2004L, 2004L, 2004L, 2004L, 2004L,
2004L, 2005L, 2005L, 2005L, 2005L, 2005L, 2005L, 2005L, 2005L,
2005L, 2005L, 2005L, 2005L, 2005L, 2005L, 2005L, 2005L, 2005L,
2005L, 2005L, 2005L, 2005L, 2006L, 2006L, 2006L, 2006L, 2006L,
2006L, 2006L, 2006L, 2006L, 2006L, 2006L, 2006L, 2006L, 2006L,
2006L, 2006L, 2006L, 2006L, 2006L, 2006L, 2006L, 2007L, 2007L,
2007L, 2007L, 2007L, 2007L, 2007L, 2007L, 2007L, 2007L, 2007L,
2007L, 2007L, 2007L, 2007L, 2007L, 2007L, 2007L, 2007L, 2007L,
2007L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L,
2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L, 2008L,
2008L, 2008L, 2008L, 2008L, 2009L, 2009L, 2009L, 2009L, 2009L,
2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L,
2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2009L, 2010L, 2010L,
2010L, 2010L, 2010L, 2010L, 2010L, 2010L, 2010L, 2010L, 2010L,
2010L, 2010L, 2010L, 2010L, 2010L, 2010L, 2010L, 2010L, 2010L,
2010L, 2011L, 2011L, 2011L, 2011L, 2011L, 2011L, 2011L, 2011L,
2011L, 2011L, 2011L, 2011L, 2011L, 2011L, 2011L, 2011L, 2011L,
2011L, 2011L, 2011L, 2011L, 2012L, 2012L, 2012L, 2012L, 2012L,
2012L, 2012L, 2012L, 2012L, 2012L, 2012L, 2012L, 2012L, 2012L,
2012L, 2012L, 2012L, 2012L, 2012L, 2012L, 2012L, 2013L, 2013L,
2013L, 2013L, 2013L, 2013L, 2013L, 2013L, 2013L, 2013L, 2013L,
2013L, 2013L, 2013L, 2013L, 2013L, 2013L, 2013L, 2013L, 2013L,
2013L, 2014L, 2014L, 2014L, 2014L, 2014L, 2014L, 2014L, 2014L,
2014L, 2014L, 2014L, 2014L, 2014L, 2014L, 2014L, 2014L, 2014L,
2014L, 2014L, 2014L, 2014L, 2015L, 2015L, 2015L, 2015L, 2015L,
2015L, 2015L, 2015L, 2015L, 2015L, 2015L, 2015L, 2015L, 2015L,
2015L, 2015L, 2015L, 2015L, 2015L, 2015L, 2015L, 2016L, 2016L,
2016L, 2016L, 2016L, 2016L, 2016L, 2016L, 2016L, 2016L, 2016L,
2016L, 2016L, 2016L, 2016L, 2016L, 2016L, 2016L, 2016L, 2016L,
2016L, 2017L, 2017L, 2017L, 2017L, 2017L, 2017L, 2017L, 2017L,
2017L, 2017L, 2017L, 2017L, 2017L, 2017L, 2017L, 2017L, 2017L,
2017L, 2017L, 2017L, 2017L, 2018L, 2018L, 2018L, 2018L, 2018L,
2018L, 2018L, 2018L, 2018L, 2018L, 2018L, 2018L, 2018L, 2018L,
2018L, 2018L, 2018L, 2018L, 2018L, 2018L, 2018L, 2019L, 2019L,
2019L, 2019L, 2019L, 2019L, 2019L, 2019L, 2019L, 2019L, 2019L,
2019L, 2019L, 2019L, 2019L, 2019L, 2019L, 2019L, 2019L, 2019L,
2019L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L,
2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L, 2020L,
2020L, 2020L, 2020L, 2020L), year_2 = c(2000L, 2001L, 2002L,
2003L, 2004L, 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L,
2012L, 2013L, 2014L, 2015L, 2016L, 2017L, 2018L, 2019L, 2020L,
2000L, 2001L, 2002L, 2003L, 2004L, 2005L, 2006L, 2007L, 2008L,
2009L, 2010L, 2011L, 2012L, 2013L, 2014L, 2015L, 2016L, 2017L,
2018L, 2019L, 2020L, 2000L, 2001L, 2002L, 2003L, 2004L, 2005L,
2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L, 2014L,
2015L, 2016L, 2017L, 2018L, 2019L, 2020L, 2000L, 2001L, 2002L,
2003L, 2004L, 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L,
2012L, 2013L, 2014L, 2015L, 2016L, 2017L, 2018L, 2019L, 2020L,
2000L, 2001L, 2002L, 2003L, 2004L, 2005L, 2006L, 2007L, 2008L,
2009L, 2010L, 2011L, 2012L, 2013L, 2014L, 2015L, 2016L, 2017L,
2018L, 2019L, 2020L, 2000L, 2001L, 2002L, 2003L, 2004L, 2005L,
2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L, 2014L,
2015L, 2016L, 2017L, 2018L, 2019L, 2020L, 2000L, 2001L, 2002L,
2003L, 2004L, 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L,
2012L, 2013L, 2014L, 2015L, 2016L, 2017L, 2018L, 2019L, 2020L,
2000L, 2001L, 2002L, 2003L, 2004L, 2005L, 2006L, 2007L, 2008L,
2009L, 2010L, 2011L, 2012L, 2013L, 2014L, 2015L, 2016L, 2017L,
2018L, 2019L, 2020L, 2000L, 2001L, 2002L, 2003L, 2004L, 2005L,
2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L, 2014L,
2015L, 2016L, 2017L, 2018L, 2019L, 2020L, 2000L, 2001L, 2002L,
2003L, 2004L, 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L,
2012L, 2013L, 2014L, 2015L, 2016L, 2017L, 2018L, 2019L, 2020L,
2000L, 2001L, 2002L, 2003L, 2004L, 2005L, 2006L, 2007L, 2008L,
2009L, 2010L, 2011L, 2012L, 2013L, 2014L, 2015L, 2016L, 2017L,
2018L, 2019L, 2020L, 2000L, 2001L, 2002L, 2003L, 2004L, 2005L,
2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L, 2014L,
2015L, 2016L, 2017L, 2018L, 2019L, 2020L, 2000L, 2001L, 2002L,
2003L, 2004L, 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L,
2012L, 2013L, 2014L, 2015L, 2016L, 2017L, 2018L, 2019L, 2020L,
2000L, 2001L, 2002L, 2003L, 2004L, 2005L, 2006L, 2007L, 2008L,
2009L, 2010L, 2011L, 2012L, 2013L, 2014L, 2015L, 2016L, 2017L,
2018L, 2019L, 2020L, 2000L, 2001L, 2002L, 2003L, 2004L, 2005L,
2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L, 2014L,
2015L, 2016L, 2017L, 2018L, 2019L, 2020L, 2000L, 2001L, 2002L,
2003L, 2004L, 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L,
2012L, 2013L, 2014L, 2015L, 2016L, 2017L, 2018L, 2019L, 2020L,
2000L, 2001L, 2002L, 2003L, 2004L, 2005L, 2006L, 2007L, 2008L,
2009L, 2010L, 2011L, 2012L, 2013L, 2014L, 2015L, 2016L, 2017L,
2018L, 2019L, 2020L, 2000L, 2001L, 2002L, 2003L, 2004L, 2005L,
2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L, 2014L,
2015L, 2016L, 2017L, 2018L, 2019L, 2020L, 2000L, 2001L, 2002L,
2003L, 2004L, 2005L, 2006L, 2007L, 2008L, 2009L, 2010L, 2011L,
2012L, 2013L, 2014L, 2015L, 2016L, 2017L, 2018L, 2019L, 2020L,
2000L, 2001L, 2002L, 2003L, 2004L, 2005L, 2006L, 2007L, 2008L,
2009L, 2010L, 2011L, 2012L, 2013L, 2014L, 2015L, 2016L, 2017L,
2018L, 2019L, 2020L, 2000L, 2001L, 2002L, 2003L, 2004L, 2005L,
2006L, 2007L, 2008L, 2009L, 2010L, 2011L, 2012L, 2013L, 2014L,
2015L, 2016L, 2017L, 2018L, 2019L, 2020L), name_count = c(0L,
0L, 1L, 3L, 1L, 1L, 4L, 1L, 3L, 2L, 3L, 3L, 1L, 2L, 4L, 0L, 4L,
4L, 3L, 1L, 1L, 3L, 1L, 2L, 5L, 2L, 2L, 1L, 0L, 3L, 2L, 1L, 4L,
0L, 2L, 4L, 2L, 3L, 4L, 2L, 2L, 1L, 2L, 2L, 1L, 4L, 3L, 2L, 2L,
0L, 0L, 0L, 3L, 2L, 2L, 2L, 1L, 3L, 3L, 2L, 3L, 6L, 1L, 1L, 1L,
1L, 3L, 2L, 1L, 2L, 4L, 2L, 3L, 1L, 5L, 1L, 3L, 1L, 1L, 0L, 0L,
1L, 1L, 2L, 3L, 6L, 3L, 1L, 3L, 1L, 1L, 2L, 3L, 1L, 2L, 4L, 1L,
1L, 3L, 2L, 5L, 4L, 3L, 2L, 5L, 4L, 4L, 2L, 6L, 3L, 5L, 1L, 1L,
4L, 2L, 2L, 2L, 2L, 2L, 0L, 2L, 4L, 3L, 0L, 3L, 0L, 2L, 2L, 2L,
3L, 5L, 0L, 1L, 4L, 2L, 2L, 2L, 4L, 7L, 1L, 1L, 1L, 2L, 2L, 0L,
1L, 2L, 1L, 1L, 2L, 4L, 3L, 2L, 1L, 5L, 3L, 4L, 3L, 5L, 0L, 4L,
2L, 3L, 1L, 5L, 2L, 3L, 2L, 0L, 5L, 3L, 5L, 2L, 9L, 1L, 3L, 2L,
2L, 1L, 0L, 1L, 3L, 1L, 3L, 1L, 2L, 4L, 3L, 3L, 1L, 3L, 1L, 2L,
1L, 3L, 1L, 5L, 2L, 4L, 1L, 2L, 5L, 1L, 3L, 3L, 1L, 5L, 1L, 3L,
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1L, 0L, 6L, 3L, 1L, 4L, 1L, 1L, 2L, 5L, 2L, 3L, 2L, 2L, 2L, 4L,
0L, 1L, 3L, 0L, 3L, 2L, 1L, 4L, 1L, 8L, 4L, 6L, 1L, 3L, 3L, 3L,
1L, 2L, 1L, 1L, 0L, 1L, 4L, 1L, 1L, 1L, 2L, 3L, 3L, 3L, 0L, 1L,
2L, 4L, 2L, 2L, 3L, 0L, 2L, 4L, 2L, 2L, 1L, 2L, 2L, 1L, 3L, 3L,
1L, 3L, 2L, 4L, 1L, 1L, 4L, 3L, 5L, 1L, 6L, 1L, 4L, 0L, 4L, 2L,
0L, 1L, 4L, 2L, 1L, 1L, 3L, 2L, 1L, 2L, 3L, 2L, 3L, 3L, 1L, 2L,
3L, 1L, 0L, 4L, 2L, 2L, 1L, 3L, 3L, 2L, 1L, 1L, 0L, 1L, 3L, 2L,
2L, 5L, 0L, 3L, 3L, 3L, 3L, 1L, 1L, 6L, 2L, 2L, 4L, 2L, 6L, 1L,
5L, 2L, 2L, 1L, 2L, 2L, 0L, 0L, 1L, 2L, 3L, 2L, 4L, 0L, 6L, 1L,
0L, 0L, 2L, 3L, 7L, 2L, 1L, 2L, 2L, 0L, 1L, 2L, 1L, 1L, 3L, 1L,
1L, 4L, 2L, 6L, 2L, 1L, 4L, 5L, 2L, 3L, 4L, 3L, 2L, 3L, 7L, 2L,
3L, 4L, 2L, 2L, 2L, 2L, 1L, 3L, 2L, 0L, 0L, 2L, 0L, 0L, 0L, 1L,
0L, 2L, 0L, 2L, 2L, 2L, 1L, 0L, 0L, 2L, 3L, 4L, 7L, 3L, 3L, 1L,
1L, 1L, 3L, 2L, 2L, 1L, 4L, 2L)), row.names = c(NA, -441L), class = "data.frame")