I am trying to sort the graph by count, but I am not clearly getting how I can. Important thing is that 'topic' is a discrete variable and I'm just showing the count of each topic through the whole data set. This is the code I am using:
ggplot(data = dtd, aes(x = topic)) + geom_bar(fill = "lightblue", colour = "black") + coord_polar()
And this is the error when I try to reorder:
ggplot(data = dtd, aes(x = reorder(topic))) + geom_bar(fill = "lightblue", colour = "black") + coord_polar()
Error in tapply(X = X, INDEX = x, FUN = FUN, ...) :
argument "X" is missing, with no default
It'd be a plus if someone might say how I could fill those sections with a gradient blue shade or something pretty.
The error is coming from reorder not having a second vector of values to reorder by. You could supply one by counting up your data ahead of passing to ggplot, then reordering it by the new variable:
library(dplyr)
library(ggplot2)
df <- tibble(Topic = c(rep("A", 55), rep("B", 22), rep("C", 40), rep("D", 100)))
df %>%
group_by(Topic) %>%
summarise(freq = n()) %>%
ggplot(aes(x = reorder(Topic, freq), y = freq)) +
geom_bar(fill = "lightblue", colour = "black", stat = "identity") +
coord_polar()
There may be smoother ways of doing it, but this keeps the reorder function you were using before.