Histogram with ggplot2 requires a continuous x variable - linux

Question

I have a dataset in a table format that looks like this:
test frequency
1 test40 3
2 test33 5
3 test19 2
4 test4521 1
5 test34 1
6 test27 3
7 test42 3
8 test35 1
....
If I use this command:
library(ggplot2)
ggplot(t, aes("frequency")) +
geom_histogram()
("t" is the name of my table)
Then RStudio says: "StatBin requires a continuous x variable: the x variable is discrete. Perhaps you want stat="count"?"
I just want to see how many times a 3 or a 5 etc. occurs.
Thanks for your help.

Answer 1

It looks like your data is already aggregated? Maybe the ggplot2::geom_histogram() function might not appropriate for you to use? Have you tried the geom_col() function? This simply takes the numbers declared in the input data frame, and displays a column plot with that data.
Using the below code
# Declare data frame
t <- data.frame(test = c("test40", "test33", "test19", "test4521",
"test34", "test27", "test42", "test35"),
frequency = c(3, 5, 2, 1,
1, 3, 3, 1))
returns the data frame like this
# View data
print(t)
test frequency
1 test40 3
2 test33 5
3 test19 2
4 test4521 1
5 test34 1
6 test27 3
7 test42 3
8 test35 1
and therefore you can plot it like this
# Load package
library(ggplot2)
# Generate column plot
ggplot(t, aes(test, frequency)) +
geom_col()
If you simply wanted a count of the times that the number 2 or the number 3 occurred in your data frame, then yes the geom_histogram() is the correct function to use. See, the geom_histogram() function counts the frequency that a term occurs in the data frame, then returns the result. It has an internal validation that looks at the type of data that you are trying to plot across the x-axis, and notices that if it is discrete, then you need to parse the parameter stat="count" in the function. If you don't include this parameter, then ggplot will try to bin your data to create the histogram, which is illogical because all you want is a count.
Check out this link for a description of the difference between continuous and discrete data: What is the difference between discrete data and continuous data?
With this in mind, you can plot the histogram like this
# Generate histogram plot
ggplot(t, aes(frequency)) +
geom_histogram(stat="count")
I hope that helps mate.