How to Draw a Horizontal Barplot in R

A barplot is a representation of data in form of the bar the height of bar represents the number of values. In this article, we will discuss How to Draw a Horizontal Barplot in R programming language. 

R language supports two ways to plot a bar plot, and we will discuss how this can be modified to be put to our use.

Method 1: Using barplot()

R Language uses the function barplot() to create bar charts. Here, both vertical and Horizontal bars can be drawn.

Syntax: barplot(H, xlab, ylab, main, names.arg, col)

Parameters:

• H: This parameter is a vector or matrix containing numeric values which are used in bar chart.
• xlab: This parameter is the label for x axis in bar chart.
• ylab: This parameter is the label for y axis in bar chart.
• main: This parameter is the title of the bar chart.
• names.arg: This parameter is a vector of names appearing under each bar in bar chart.
• col: This parameter is used to give colors to the bars in the graph.

The bar function has a field named “horiz” keep that field value “True” to create the bar plot horizontally.

Example:

R

# Create example data
data <- data.frame(x_axis = (1:10),
                   y_axis = 9:0)

# barplot() function is used to
# plot the bar and horiz field is
# used to plot bar horizontally
barplot(data$x_axis ~ data$y_axis,
        horiz = TRUE)

Output:

fig 1: Horizontal bar plot

Method 2: Using GGPLOT2

In this method, we draw the bar plot using the ggplot2 function. ggplot2 have a function named geom_bar() which is used to plot the horizontal bar, and we put our data into the geom_bar function with ggplot() to plot the bar. At last, we will flip the whole plot using the coord_flip() function. A flipped vertical plot will generate a horizontal plot.

Example:

R

# load the library
library("ggplot2")

# data frame created
data <- data.frame(x_axis = (1:10),
                   y_axis = 9:0)

# bar is created with the help of
# grom_bar() and ggplot() function
ggp <- ggplot(data, aes(x_axis, y_axis)) +
  geom_bar(stat = "identity")

# complete graph get flipped with the
# help of coord_flip() function
ggp +  coord_flip()

Output:

fig 2: Horizontal bar plot