R – Pie Charts

A pie chart is a circular statistical graphic, which is divided into slices to illustrate numerical proportions. It depicts a special chart that uses “pie slices”, where each sector shows the relative sizes of data. A circular chart cuts in a form of radii into segments describing relative frequencies or magnitude also known as a circle graph. 

R – Pie Charts

R Programming Language uses the function pie() to create pie charts. It takes positive numbers as a vector input. 

Syntax: pie(x, labels, radius, main, col, clockwise)

Parameters:

• x: This parameter is a vector that contains the numeric values which are used in the pie chart.
• labels: This parameter gives the description to the slices in pie chart.
• radius: This parameter is used to indicate the radius of the circle of the pie chart.(value between -1 and +1).
• main: This parameter is represents title of the pie chart.
• clockwise: This parameter contains the logical value which indicates whether the slices are drawn clockwise or in anti clockwise direction.
• col: This parameter give colors to the pie in the graph.

Creating a simple pie chart

To create a simple pie chart: 

• By using the above parameters, we can draw a pie chart.
• It can be described by giving simple labels.

Example:

R

# Create data for the graph.
geeks<- c(23, 56, 20, 63)
labels <- c("Mumbai", "Pune", "Chennai", "Bangalore")

# Plot the chart.
pie(geeks, labels)

Output:

Pie chart including the title and colors

To create color and title pie chart. 

• Take all parameters which are required to make pie chart by giving a title to the chart and add labels.
• We can add more features by adding more parameters with more colors to the points.

Example:

R

# Create data for the graph.
geeks<- c(23, 56, 20, 63)
labels <- c("Mumbai", "Pune", "Chennai", "Bangalore")

# Plot the chart with title and rainbow
# color pallet.
pie(geeks, labels, main = "City pie chart",
            col = rainbow(length(geeks)))

Output:

Slice Percentage & Chart Legend

To create chart legend and slice percentage, we can plot by doing the below methods. 

• There are two more properties of the pie chart: 
  • slice percentage
  • chart legend.
• We can show the chart in the form of percentages as well as add legends.

Example:

R

# Create data for the graph.
geeks <- c(23, 56, 20, 63)
labels <- c("Mumbai", "Pune", "Chennai", "Bangalore")

piepercent<- round(100 * geeks / sum(geeks), 1)

# Plot the chart.
pie(geeks, labels = piepercent,
    main = "City pie chart", col = rainbow(length(geeks)))
legend("topright", c("Mumbai", "Pune", "Chennai", "Bangalore"),
                    cex = 0.5, fill = rainbow(length(geeks)))

Output:

3D Pie Chart

Here we are going to create a 3D Pie chart using plotrix package and then we will use pie3D() function to plot 3D plot.

R

# Get the library.
library(plotrix)

# Create data for the graph.
geeks <- c(23, 56, 20, 63)
labels <- c("Mumbai", "Pune", "Chennai", "Bangalore")

piepercent<- round(100 * geeks / sum(geeks), 1)

# Plot the chart.
pie3D(geeks, labels = piepercent,
    main = "City pie chart", col = rainbow(length(geeks)))
legend("topright", c("Mumbai", "Pune", "Chennai", "Bangalore"),
                    cex = 0.5, fill = rainbow(length(geeks)))

Output: