R Plot - Pie Chart

R provides a large number of libraries to implement drawing functions.

A pie chart, also known as a pie-shaped chart, is a circular statistical chart divided into several sectors, used to describe the relative relationships between quantities, frequencies, or percentages.

R uses the pie() function to implement pie charts, with the syntax format as follows:

pie(x, labels = names(x), edges =　200, radius = 0.8,
　　　　clockwise = FALSE, init.angle = if(clockwise)　90 else 0,
　　　　density = NULL, angle =　45, col = NULL, border = NULL,
　　　　lty = NULL, main = NULL, ...)

• x: Numeric vector, representing the area of each sector.

• labels: Character vector, representing the area labels of each sector.

• edges: This parameter is not very useful, indicating the number of sides of the polygon (the outline of a circle is similar to a polygon with many sides).

• radius: The radius of the pie chart.

• main: The title of the pie chart.

• clockwise: A logical value indicating whether the slices of the pie chart are divided in a clockwise direction.

• angle: Sets the slope of the texture.

• density: The density of the texture. The default value is NULL.

• col: Represents the color of each sector, which is equivalent to a palette.

To draw a pie chart, you need to prepare these: a vector reflecting the quantity, labels for each part, and colors for each part (optional).

Next, let's draw a simple pie chart:

#　Data Preparation
info　=　c(1,　2,　4,　8)
#　Naming
names　=　c("Google",　"w3codebox",　"Taobao",　"Weibo")
#　Coloring (optional)
cols　=　c("#ED1C24","#22B14C","#FFC90E","#3f48CC")
#　Plotting
pie(info, labels=names, col=cols)

Executing the plotting program will generate a PDF file (Rplots.pdf) in the current directory. Open the file to see the graphic effect as follows:

We can also use png(), jpeg(), bmp() functions to set the output file format to image:

#　Data Preparation
info　=　c(1,　2,　4,　8)
#　Naming
names　=　c("Google",　"w3codebox",　"Taobao",　"Weibo")
#　Coloring (optional)
cols　=　c("#ED1C24","#22B14C","#FFC90E","#3f48CC")
# Set output image
png(file='w3codebox-pie.png', height=300, width=300)
#　Plotting
pie(info, labels=names, col=cols)

Next, we set the title for the pie chart, the Chinese font needs to set the font parameter family='GB'1You can also set your own font library, for details, please refer to:R Plotting - Chinese Support。

#　Data Preparation
info　=　c(1,　2,　4,　8)
#　Naming
names　=　c("Google",　"w3codebox",　"Taobao",　"Weibo")
#　Coloring (optional)
cols　=　c("#ED1C24","#22B14C","#FFC90E","#3f48CC")
#　Calculate Percentage
piepercent　=　paste(round(100*info/sum(info)),　"%")
#　Plotting
pie(info,　labels=piepercent,　main　=　"Website Analysis",　col=cols,　family='GB1')
#　Add color sample annotation
legend("topright",　names,　cex=0.8,　fill=cols)

If you want to draw 3D pie chart, you can use the pie function of the plotrix library3D() function, we need to install it first before using:

install.packages("plotrix",　repos　=　"https://mirrors.ustc.edu.cn/CRAN/)

#　Load　plotrix
library(plotrix)
#　Data Preparation
info　=　c(1,　2,　4,　8)
#　Naming
names　=　c("Google",　"w3codebox",　"Taobao",　"Weibo")
#　Coloring (optional)
cols　=　c("#ED1C24","#22B14C","#FFC90E","#3f48CC")
#　Set file name, output as　png
png(file　=　"3d_pie_chart.png")
#　Drawing　3D　图，family　to set the Chinese font library supported by your system
pie3D(info,labels　=　names,explode　=　0.1,　main　=　"3D　图,family　=　"STHeitiTC"-Light")

The generated image is as follows: