[R] Flip heatmap color range in base R?

[Bert Gunter]

?heatmap     (carefully!)

and note the reference to "col" in the "..." argument (and the need to
consult ?image).

I suspect that your other questions can be similarly answered by a careful
reading of the Help file, but I have not checked. You should.

Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Sun, May 12, 2019 at 11:02 AM Serena De Stefani <
serenadestefani using gmail.com> wrote:

> I am building a simple heat map in base R.
> This is my matrix:
>
>     stleft = matrix(
>          c(0,5,5,2,6,8,4,6,9),
>          nrow=3,
>          ncol=3)
>     colnames(stleft) <- c("Narrow","Wide", "Wider")
>     rownames(stleft) <- c("Person", "Object","Bare")
>     stleft
>
>
> The matrix looks like this:
>
>     > stleft
>            Narrow Wide Wider
>     Person      0    2     4
>     Object      5    6     6
>     Bare        5    8     9
>
> To build the heat map I simply run:
>
>     heatmap(stleft, Colv = NA, Rowv = NA, scale = "none")
>
> You may see it here: https://i.stack.imgur.com/KCblOm.png
>
> As you can see the "0" (corresponding to the narrow/person cell) appears as
> a deep red while the "9" (corresponding to the wider/bare cell) appears as
> light yellow.
>
> - How can I "flip" this range so that the "0" appears in a light color and
> the "9" in a deep color?
>
> I have also three other questions (less important at the moment):
>
> - How can I have a heat map with the same row/column order as my original
> matrix?
>
> - Why is the image truncated? It appears truncated in the RStudio plot
> panel and it is saved truncated. I have tried to enlarge the plot panel in
> R Studio to no avail.
>
> - How can I insert numbers in the cells?
>
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>
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