ColSideColors' must be a character vector of length ncol(x)

Question

[Jakpa]

Hello all, I tried to generate a heatmap using heatmap.2 The following code was used:

<code>heatmap.2(as.matrix(sample_dist), key=F, trace="none",Colv = c("cancer", "normal"),Rowv ="Colv",dendrogram= "none",col=colorpanel(100, "black", "white"),ColSideColors=myColors[condn], RowSideColors=myColors[condn],margin=c(10, 10), main="Sample Distance Matrix")

Then, I got this error:

<code>Error in heatmap.2(as.matrix(sample_dist), key = F, trace = "none", Colv = c("cancer", : 'ColSideColors' must be a character vector of length ncol(x)

Does this mean that "myColors" is not same as "condn"?

This was how i defined myColors and "condn"

<code>myColors<- brewer.pal(8, "Set3")[1:length(unique(group))]
<code>condn<- factor(c(rep("normal",3), rep("cancer",3)))

where, am I getting it wrong?

Regards, Anthony

[Jakpa]

Hello Kelvin, pardon my formatting style. I am still learning it

Answer 1

[Kevin Blighe]

It is likely that, when you solve this first error, a subsequent error will appear relating to RowSideColors.

The only thing that you need to pass to ColSideColors and RowSideColors are character vectors of colours that have the same length as ncol(x) and nrow(x), respectively.

• What, currently, is contained in myColours?
• What is group?
• What are you aiming to do with this: myColors[condn]?

At the very fundamental level, we can assign a pre-defined colour palette like this:

samples <- c('Primary','Primary','Normal','Met','Normal','Normal','Met','Met','Primary','Normal')
samples <- factor(samples, levels = c('Normal', 'Primary', 'Met'))
RColorBrewer::brewer.pal(11, 'Spectral')[samples]
 [1] "#D53E4F" "#D53E4F" "#9E0142" "#F46D43" "#9E0142" "#9E0142" "#F46D43" "#F46D43" "#D53E4F" "#9E0142"

Other ways to assign colours to factors:

colorRampPalette(c('pink', 'purple', 'red4'))(length(unique(samples)))[samples]
 [1] "#A020F0" "#A020F0" "#FFC0CB" "#8B0000" "#FFC0CB" "#FFC0CB" "#8B0000" "#8B0000" "#A020F0"
[10] "#FFC0CB"

...or even just:

c('pink', 'purple', 'red4')[samples]
 [1] "purple" "purple" "pink"   "red4"   "pink"   "pink"   "red4"   "red4"   "purple" "pink"

Gracias!

Kevin

[Jakpa]

Hi Kelvin, Thank you for your response.

This is what is in myColors: [1] "#8DD3C7" "#FFFFB3"

 for 'group'  I have this:

factor w/2 levels "HBR; "UHR" : 1 1 1 2 2 2>`

condn

factor w/2 levels "cancer", "normal" : 2 2 2 1 1 1

The 'group' and 'condn' are what am using for my comparison in my Differential gene Expression.

from your examples, I think I have few numbers of colors compare to what i have in "group" and "condn".

How do I make this up?

Am relatively new with R

Thank you,
Anthony

[Kevin Blighe]

Can you try to re-format your post? - thanks!

[Jakpa]

Hello Kelvin,

I hope the re-formatted post is ok. am still learning learning how to write codes in this Platform.

Regards

[Kevin Blighe]

You have 2 colours and 2 groups? If that is the case, then this should work

myColors[condn]

...or:

myColors[group]

For RowSideColors, it is a different problem - I recommend that you avoid using that, for now.

[Jakpa]

Hi Kelvin, I saw the error. It was from sample_dist

I tranposed the matrix like this:

 <code>sample_dist<- as.matrix(dist(t(assay(rlog_Trans))))

The heatMap is ok now with both groups

Thanks