How to create pie chart and bar chart in R rogramming
Pie Chart
In R the pie chart is created using the pie() function
which takes positive numbers as a vector input. The additional parameters are
used to control labels, color, title etc.
Syntax
The basic syntax for creating a pie-chart using the R is
pie(x, labels, radius, main, col, clockwise)
Following is the description of the parameters used −
·
x is a vector containing the numeric values used in the
pie chart.
·
labels is used to give description to the slices.
·
radius indicates the radius of the circle of the pie
chart.(value between −1 and +1).
·
main indicates the title of the chart.
·
col indicates the color palette.
·
clockwise is a logical value indicating if the slices are drawn
clockwise or anti clockwise.
Example
A very simple pie-chart is created using just the input
vector and labels. The below script will create and save the pie chart in the
current R working directory.
# Create data for the graph.
x <- c(21, 62, 10, 53)
labels <- c("London", "New York", "Singapore",
"Mumbai")
# Plot the chart.
pie(x,labels)
Pie Chart Title and Colors
We can expand the features of the chart by adding
more parameters to the function. We will use parameter main to
add a title to the chart and another parameter is col which
will make use of rainbow colour pallet while drawing the chart. The length of
the pallet should be same as the number of values we have for the chart. Hence
we use length(x).
Example
The below script will create and save the pie chart
in the current R working directory.
# Create data for the graph.
x <- c(21, 62, 10, 53)
labels <- c("London", "New York", "Singapore",
"Mumbai")
# Plot the chart with title and rainbow color pallet.
pie(x, labels, main = "City pie chart", col =
rainbow(length(x)))
Slice Percentages and Chart Legend
We can add slice percentage and a chart legend 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)
# 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)))
3D Pie Chart
A pie chart with 3 dimensions can be drawn using
additional packages. The package plotrix has a function
called pie3D() that is used for this.
# Get the library.
library(plotrix)
# Create data for the graph.
x <- c(21, 62, 10,53)
lbl <- c("London","New
York","Singapore","Mumbai")
# Plot the chart.
pie3D(x,labels = lbl,explode = 0.1, main = "Pie Chart
of Countries ")
Bar chart
A bar chart represents data in rectangular bars with length
of the bar proportional to the value of the variable. R uses the function barplot() to
create bar charts. R can draw both vertical and Horizontal bars in the bar
chart. In bar chart each of the bars can be given different colors.
Syntax
The basic syntax to create a bar-chart in R is −
barplot(H,xlab,ylab,main, names.arg,col)
Following is the description of the parameters used −
- H is a vector or matrix containing numeric values
used in bar chart.
- xlab is the label for x axis.
- ylab is the label for y axis.
- main is the title of the bar chart.
- names.arg is a vector of names appearing under each bar.
- col is used to give colors to the bars in the graph.
Example
A simple bar chart is created using just the input vector
and the name of each bar.
The below script will create and save the bar chart in the
current R working directory.
# Create the data for the chart
H <- c(7,12,28,3,41)
# Plot the bar chart
barplot(H)
Bar Chart Labels, Title and Colors
The features of the bar chart can be expanded by
adding more parameters. The main parameter is used to
add title. The col parameter is used to add colors
to the bars. The args.name is a vector having same number of
values as the input vector to describe the meaning of each bar.
Example
The below script will create and save the bar chart
in the current R working directory.
# Create the data for the chart
H <- c(7,12,28,3,41)
M <- c("Mar","Apr","May","Jun","Jul")
# Plot the bar chart
barplot(H,names.arg=M,xlab="Month",ylab="Revenue",col="blue",
main="Revenue chart",border="red")
Group Bar Chart and Stacked Bar Chart
We can create bar chart with groups of bars and
stacks in each bar by using a matrix as input values.
More than two variables are represented as a matrix
which is used to create the group bar chart and stacked bar chart.
# Create the input vectors.
colors = c("green","orange","brown")
months <- c("Mar","Apr","May","Jun","Jul")
regions <- c("East","West","North")
# Create the matrix of the values.
Values <- matrix(c(2,9,3,11,9,4,8,7,3,12,5,2,8,10,11), nrow = 3, ncol = 5, byrow = TRUE)
# Create the bar chartbarplot(Values, main = "total revenue", names.arg = months, xlab = "month", ylab = "revenue", col = colors)
# Add the legend to the chartlegend("topleft", regions, cex = 1.3, fill = colors)
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