R - Ggplot2 - Highlighting Selected Points and Strange Behavior

Subsetting and highlighting multiple data points in ggplot

I would guess that if you want different colors for different subsets of your data these subsets represent different groups. The usual way to deal with this in ggplot would to create a group variable. In ggplot you then can easily set the color aesthetic to your group.

library(ggplot2)
a <- 1:50
b <- rnorm(50)
mydata <- data.frame(a=a, b=b)
mydata$group        <- "a" 
mydata$group[1:9]   <- "b"
mydata$group[10:30] <- "c"
mydata$group[40:50] <- "d"

ggplot(mydata,aes(x=a,y=b, col = group)) + 
  geom_point() +
  scale_color_manual(values=c("blue", "green", "red", "cyan"), guide = FALSE) 

If you want a bar plot you have to set stat = "identity" like this:

ggplot(mydata,aes(x=a,y=b, col = group, fill = group)) + 
  geom_bar(stat = "identity") +
  scale_color_manual(values=c("blue", "green", "red", "cyan"), guide = FALSE) +
  scale_fill_manual(values=c("blue", "green", "red", "cyan"), guide = FALSE)

Highlight all values from a group on hover

this will probably suit your needs

sample data

set.seed(357)
xy <- data.frame(letters = rep(c("a", "b", "c"), times = 3),
                 values = runif(9),
                 groups = rep(c("group1", "group2", "group3"), each = 3))

plotting

#create a SharedData object for use in the ggplot below, group by 'groups' 
d <- highlight_key(xy, ~groups )

#create a normal ggplot to fit your needs, but use the SharedData object as data for the chart
p <- ggplot( d, aes(x = letters, y = values, group = groups)) + theme_bw() + geom_point()

#now ggplotly the newly created ggplot, and add text for the tooltips as needed
gg <- ggplotly( p, tooltip = "groups" )

#set the highlight-options to your liking, and plot...
highlight( gg, on = "plotly_hover", off = "plotly_deselect", color = "red" )

plot results

Change color for specific data in ggplot2

After renkler variable:

renkler[1]= "#DA0018"
renkler[7]= "#DA0018"

For the legend title:

scale_color_manual(values = renkler, name="new name")

Highlight dots in boxplots

Changing the value of color to a logical test will let you get partway to you goals. Use this for the geom_point call

geom_point(aes(color = (expression > 0) )

This would get the labels right but the legend title will look odd:

geom_point(aes(color = c("LT 0", "GT 0")[1+(expression > 0)] )

To fix the legend title add this:

... +  guides(color = guide_legend(title= "Above or Below zero"))+ ...

I found that changing the color to be a text value rather strange but changing the argument to fill failed. I suppose this does make sense because it was the color aesthetic that is being made "legendary".

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