R Bar Graphs

 A Bar graph is a pictorial representation of The numerical data By a number of Bars of uniform width erected horizontally or vertically with equally spacing between them.

Bar Graph rules

A good bar graph should have:

• A clear and accurate title that explains the purpose of the graph
• Bars that are either labelled directly or indicated by means of a color key
• An X and Y axis that are labelled
• Bars should not be touching one another.The source of the data.

 Which Bar Graphs do you think are the best here?

In R, we can create a bar chart to visualize the data in an efficient manner. For this purpose, R provides the barplot() function.

Note: barplot() This function also takes negative numbers in the vector.

Syntax for R Bar Chart(barplot())

barplot(vector/matrix, names.arg, xlab, ylab, main, horiz, col, border, beside, xlim, ylim)

Following arguments in details.

S.No	Parameter	Description
1.	vector/matrix	It is a vector or matrix which contains the numeric values.
2.	names.arg	A vector of names that appear under each bar.
3.	xlab	It is the label for the x-axis.
4.	ylab	It is the label for the y-axis.
5.	main	It is the title of the chart.
6.	col	It is used to give the color for both the points and lines
7	horiz	Optional. If you want the bar horizontal, then ‘TRUE’ is given here.
8	border	Optional. Here the border color name is given for the bars.
9	beside	Optional. If its value is given TRUE then grouped bar chart is displayed, if it is FALSE then stacked bar chart is displayed.
10	xlim	Optional. Here the limit of the x-axis is increased or decreased. By default this limit is set according to the bars.
11	ylim	Optional. Here the limit of the y-axis is increased or decreased. By default this limit is set according to the bars.

Simple Example for barplot() Function in R

Input: Simple Example for barplot() Function in R

vec = c(25,10,15,35,5) barplot(vec)

Output

Add Title , color and Labels on Bar in R

Input: To draw a bar chart using parameter main, col, xlab and ylab

vec = c(25,10,15,35,5) barplot(vec, xlab=’Student Name’, ylab=’Marks’, main=’Student Marks’, col=’red’)

Output:

Create Stacked Bar Chart using Matrix in R

For example, a stacked bar chart has been created. It is very important to have legend in this bar chart, along with this matrix is used. The legend() function is used to create the legend.

Input: To draw Stacked Bar Chart using Matrix

col = c(“red”,”green”,”blue”) stud_name = c(“Rakesh”,”Mukesh”,”Raghav”,”Ramesh”) sub = c(“Physics”,”Chemistry”,”Maths”) # Create the matrix of the values. marks = matrix(c(32,28,45,26,41,35,49,42,29,35,44,49),nrow = 3,ncol = 4,byrow = TRUE) barplot(marks, main=”Student Marks”, names.arg=stud_name, xlab=”Student Name”, ylab=”Marks”, col = col) #legend for stacked bar chart. legend(“topleft”, sub, fill = col)

output:

Create Grouped Bar Chart using Matrix in R

For example, a grouped bar chart has been displayed with the help of the parameter of this barplot() function.

Input: To draw Grouped Bar Chart using Matrix

col = c(“red”,”green”,”blue”) stud_name = c(“Rakesh”,”Mukesh”,”Raghav”,”Ramesh”) sub = c(“Physics”,”Chemistry”,”Maths”) # Create the matrix of the values. marks = matrix(c(32,28,45,26,30,35,49,42,29,35,44,49), nrow = 3, ncol = 4, byrow = TRUE) barplot(marks, main=”Student Marks”, names.arg=stud_name, xlab=”Student Name”, ylab=”Marks”, col = col, beside=TRUE) #legend for grouped bar chart. legend(“topleft”, sub, fill = col)

output: