How can I color a specific bar in a bar plot (qplot, ggplot2)
I plotted a facet graph using qplot and I used "fill" option to color the bars based on their values(high=Red, med=violet, low=blue)
http://i.stack.imgur.com/raEzA.png
My code is:
x = qplot(as.character(exon),Divergence_from_Ave开发者_如何学Pythonrage, data=HRA_LR,
geom="histogram",fill=abs(Divergence_from_Average))
y = x +facet_grid(~probeset_id, scales="free_x", space= "free") + theme_bw() +
opts(title="GRP78/HSPA5 (HRN vs LR)")
If I only need to color the bars which is above 0.3 and leave rest of the unfilled how can I do that?
You can tweak this to suit your needs, but here's the basic concept:
We'll define a new binary variable that determines whether or not to fill the bars. We'll pass that into the fill
argument as a factor and use scale_colour_manual
to give them the colours we want. I also passed set the colour
parameter to red so that you can see the white bars on the white background.
#Sample data
df <- data.frame(
divergence = rnorm(10),
exons = paste("E", sample(1:20, 10, TRUE), sep = ""),
probset_id = sample(letters, 10, FALSE)
)
#Binary flag for fill
df$fill <- with(df, ifelse(divergence > .3, 1,0))
ggplot(data = df, aes(as.character(exons), divergence, fill = factor(fill))) +
geom_histogram(colour = "red", legend = FALSE) +
scale_fill_manual(values = c("1" = "red", "0" = "white"), legend = FALSE) +
facet_grid(~ probset_id, scales="free_x", space= "free") +
theme_bw() + opts(title="GRP78/HSPA5 (HRN vs LR)")
Will generate something like this. I forgot to set.seed()
before saving the image so your miles may vary, but consider this a proof of concept:
Here is an example with the tips data in ggplot2
library(ggplot2)
data(tips)
qplot(day, data = tips, geom = 'blank') + geom_bar(aes(fill = ..count.. > 65))
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