R language pie chart

Grammar

The basic syntax for creating pie charts using the R language is -

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

The following is a description of the parameters used -

• x is a vector that contains the values used in the pie chart.

• Labels are used to give a description of the slice.

• Radius represents the radius of the pie circle (between the values -1 and .1).

• Main represents the title of the chart.

• col represents the palette.

• Clockwise is a logical value that indicates whether a fragment is drawn clockwise or counterclockwise.

Cases

Create a very simple pie chart with input vectors and labels. T he following script creates and saves pie charts from the current R-language working directory.

# Create data for the graph.
x <- c(21, 62, 10, 53)
labels <- c("London", "New York", "Singapore", "Mumbai")

# Give the chart file a name.
png(file = "city.jpg")

# Plot the chart.
pie(x,labels)

# Save the file.
dev.off()

When we execute the code above, it produces the following results -

Pie chart title and color

We can extend the functionality of the chart by adding more parameters to the function. W e'll use the parameter main to add a title to the chart, and the other parameter is col, which will use the rainbow slab when drawing the chart. T he length of the tray should be the same as the number of values in the chart. T herefore, we use length(x).

Cases

The following script creates and saves pie charts from the current R-language working directory.

# Create data for the graph.
x <- c(21, 62, 10, 53)
labels <- c("London", "New York", "Singapore", "Mumbai")

# Give the chart file a name.
png(file = "city_title_colours.jpg")

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

# Save the file.
dev.off()

When we execute the code above, it produces the following results -

Slice percentage and chart legend

We can add slice percentages and chart legends by creating additional chart variables.

# Create data for the graph.
x <-  c(21, 62, 10,53)
labels <-  c("London","New York","Singapore","Mumbai")

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

# Give the chart file a name.
png(file = "city_percentage_legends.jpg")

# Plot the chart.
pie(x, labels = piepercent, main = "City pie chart",col = rainbow(length(x)))
legend("topright", c("London","New York","Singapore","Mumbai"), cex = 0.8,
   fill = rainbow(length(x)))

# Save the file.
dev.off()

When we execute the code above, it produces the following results -

3D pie chart

You can use other packages to draw pie charts with 3 dimensions. T he package plotrix has a function called pie3D() for this purpose.

# Get the library.
library(plotrix)

# Create data for the graph.
x <-  c(21, 62, 10,53)
lbl <-  c("London","New York","Singapore","Mumbai")

# Give the chart file a name.
png(file = "3d_pie_chart.jpg")

# Plot the chart.
pie3D(x,labels = lbl,explode = 0.1, main = "Pie Chart of Countries ")

# Save the file.
dev.off()

When we execute the code above, it produces the following results -