alberto alberto - 1 year ago 193
R Question

ggplot: plot frequency counts of values in a dataframe (with no preprocessing)

I often find myself doing this:

# Original data
df.test <- data.frame(value=floor(rexp(10000, 1/2)))

# Compute the frequency of every value
# or the probability
freqs <- tabulate(df.test$value)
probs <- freqs / sum(freqs)

# Create a new dataframe with the frequencies (or probabilities)
df.freqs <- data.frame(n=1:length(freqs), freq=freqs, probs=probs)

# Plot them, usually in log-log
g <- ggplot(df.freqs, aes(x=n, y = freq)) + geom_point() +
scale_y_log10() + scale_x_log10()

enter image description here

Can it be done just using
without creating an intermediate dataset?

Answer Source

For frequency count, you can specify the stat parameter in geom_point as count:

ggplot(df.test, aes(x = value)) + geom_point(stat = "count") + 
    scale_x_log10() + scale_y_log10()

enter image description here

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