Data Visualization: Bar Plots

viz_bar.R

# using plot function
plot(as.factor(mtcars$cyl))

# using bar plot function
barplot(table(mtcars$cyl))

# tabulated data
cyl_freq <- table(mtcars$cyl)
cyl_freq

# horizontal bar plot
barplot(cyl_freq, horiz = TRUE)

# bar width
# equal width
barplot(cyl_freq, width = 2)

# different widths
barplot(cyl_freq, width = c(1, 1, 2))

# space between bars
barplot(cyl_freq, space = c(1, 1, 2))

# bar labels
barplot(cyl_freq, names.arg = c('Four', 'Six', 'Eight'))

# bar color
barplot(cyl_freq, col = 'blue')
barplot(cyl_freq, col = c('blue', 'red', 'green'))
barplot(cyl_freq, col = c('blue', 'red'))

# bar border color
barplot(cyl_freq, border = 'blue')

# remove axes
barplot(cyl_freq, axes = FALSE)

# axis line type
barplot(cyl_freq, axis.lty = 3)

# offset axes
barplot(cyl_freq, offset = 5)

# putting it all together
barplot(cyl_freq, col = c('blue', 'red', 'green'),
        horiz = TRUE, width = c(1, 1, 2),
        names.arg = c('Four', 'Six', 'Eight'),
        axis.lty = 2, offset = 2)

# title and axis labels
barplot(cyl_freq, col = c('blue', 'red', 'green'),
        horiz = TRUE, width = c(1, 1, 2),
        names.arg = c('Four', 'Six', 'Eight'),
        axis.lty = 2, offset = 2)
title(main = 'Distribution of Cylinders',
      xlab = 'Frequency', ylab = 'Number of Cylinders')

# bivariate plot data
table(mtcars$gear)
cyl_gear <- table(mtcars$cyl, mtcars$gear)
cyl_gear

# stacked bar plot
barplot(cyl_gear)

# bar colors
barplot(cyl_gear, col = c('blue', 'red', 'green'))

# add legend
barplot(cyl_gear, col = c('blue', 'red', 'green'),
        main = 'Gears vs Cylinders', legend.text = TRUE,
        xlab = 'Number of Gears', ylab = 'Frequency')

# grouped bar plot
barplot(cyl_gear, col = c('blue', 'red', 'green'),
        beside = TRUE, legend.text = TRUE,
        main = 'Gears vs Cylinders',
        xlab = 'Number of Gears', ylab = 'Frequency')