Barplot in R Programming

The Barplot or Bar Chart in R Programming is handy to compare the data visually. By seeing this R barplot or bar chart, One can understand, Which product is performing better compared to others. For example, If we want to compare the sales between different product categories, and product colors, we can use this bar chart.

Let us see how to Create a stacked Bar Chart, Format it’s color and borders, add legions, and Juxtapose barplot in R Programming language with an example.

Barplot Syntax

The syntax to draw the bar chart or barplot in R Programming is

barplot(height, name.args = NULL, col = NULL, main = NULL)

and the complex syntax behind this is:

barplot(height, width = 1, space = NULL, name.args = NULL, 
        legend.text = NULL, beside = FALSE, horiz = FALSE, 
        density = NULL, angle = 45, col = NULL, border = par("fg"), 
        main = NULL, sub = NULL, xlab = NULL, ylab = NULL, 
        xlim = NULL, ylim = NULL, xpd = TRUE, log = "", 
        axes = TRUE, axisnames = TRUE, cex.axis = par("cex.axis"), 
        cex.names = par("cex.axis"), inside = TRUE, plot = TRUE, 
        axis.lty = 0, offset = 0, add = FALSE, args.legend = NULL,…)

There are many arguments supported by the barplot in the R programming language to generate a bar chart. The following are the most used arguments in real-time.

  • height: You can specify either a Vector or a Matrix of values. If it is a Vector, the R bar chart is created with a sequence of rectangular bars, and each bar height depends upon the vector value. And if the height is a Matrix of values and besides is FALSE, each matrix column represents the bar, and the row values create stacked sub bars. If beside is TRUE, and height is a Matrix of values, then each matrix column represents the R Juxtaposed bar.
  • width: It is optional, but you can use this to specify the width of a bar chart.
  • space: Please specify the amount of space you want to the left before each bar of the R barplot. If the height is a Matrix of values and besides is TRUE, you have to pass two values to the space argument, where the 1st value provides space between the same group bars, and the 2nd value is space between the different columns (groups)
  • names.args: Please specify a Vector of names you want to plot below each one or group of bars in a bar chart. If we omit this argument, then it takes the names from column names if it is a matrix or the names attribute of height if it is a vector.
  • text: Please specify a Vector of text used to construct the legend for the bar chart or a Boolean value indicating whether you want to include the legend or not.
  • beside: It is a Boolean argument. If it is FALSE, the height columns are portrayed as stacked bars in R, and if it is TRUE, the columns are portrayed as Juxtaposed bars.
  • horiz: It is a Boolean argument. If it is FALSE, it drew vertically. If it is TRUE, bars drew horizontally.
  • density: Please specify the shading lines density (in lines per inch). By default, it is NULL, which means no shading lines.
  • angle: You can assign the slope of shading lines using this argument.
  • col: Please specify the vector of colors you want to use for your barplot in R. By default, it uses a set of 6-pascal colors.
  • border: Please specify the color you want to add to the borders. If you use border = NA, then borders omitted.
  • main: You can provide the Title for your R bar chart.
  • sub: You can provide the subtitle (if any).
  • xlab: Please specify the label for the barplot X-Axis
  • ylab: Please specify the label for the Y-Axis
  • xlim: This argument can help you to specify the limits for the X-Axis
  • ylim: This argument can help you to specify the barplot Y-Axis limits
  • xpad: It is a Boolean argument. Do you want to allow the bars outside the region?
  • log: You have to specify a character string of three options. If X-Axis is to be logarithmic, then “x”, If Y-Axis is to be logarithmic “y”, if both X-Axis and Y-Axis are to be logarithmic, then specify either “xy” or “yx”
  • axes: It is a Boolean argument. If it is TRUE, a vertical (or horizontal, if horiz = TRUE) axis is drawn.
  • axisnames: It is a Boolean argument. If it is TRUE, and if there is arg, the other axis is drawn (with lty = 0) and labeled in the R barplot.
  • axis: Expansion factor for numeric axis labels.
  • names: Expansion factor for labels.
  • inside: It is a Boolean argument. If it is TRUE, the lines which divide adjacent bars drew. We have to use this argument when space = 0
  • plot: It is a Boolean argument. If it is FALSE, nothing plotted
  • lty: It is a graphical parameter, which is applied to the axis and tick marks of the categorical axis.
  • offset: Please specify a vector indicating, How much the bars should shift relative to X-Axis
  • add: It is a Boolean argument, and by default, it is FALSE. If it is TRUE, bars are added to an already existing plot.
  • legend: List of arguments you want to add to the legend() function.

Create a basic bar Chart in R

In this example, we show how to create a bar chart using the vectors in R programming.

First, we declared a vector of random numbers. Next, we used the barplot function to draw the bar chart. From the below code snippet, you can observe that height is decided on the values.

values <-  c(906, 264, 689, 739, 938)

barplot(values)
Bar Chart or Barplot in R Programming 1

Create a barplot in R using CSV

In this example, we create a Bar Chart using the external data or CSV. For this, we are importing data from the CSV file using the read.csv function. I suggest you refer Read CSV article to understand the steps involved in CSV file import in R Programming.

getwd()

employee <- read.csv("Products.csv", TRUE, sep = ",", 
                     na.strings = TRUE)
data <- aggregate(employee$SalesAmount, 
                  by=list(employee$Color), 
                  FUN=sum)
print(data)

barplot(data$x, main = "Sales By Product Color")
Create a bar chart in R using CSV 2

The following statement import the data from the CSV file

employee <- read.csv("Products.csv", TRUE, sep = ",", 
                     na.strings = TRUE)

From the below code snippet, see that we used the Aggregate function to find the total amount of sales of each color. Or we can say the Sum of Sales Amount Group By Product Color.

data <- aggregate(employee$SalesAmount, 
                  by=list(employee$Color), 
                  FUN=sum)

The above statement returns the output as a List. So, we are using the $ to extract the aggregated data (sum of sales amount) from List.

barplot(data$x, main = "Sales By Product Color")

Assigning names

In this example, we assign names to R bar chart, X-Axis, Y-Axis, and individual bars using main, xlab, ylab, and names

# Assign Names to X, Y Axis Example
getwd()

employee <- read.csv("Products.csv", TRUE, sep = ",", 
                     na.strings = TRUE)
output <- aggregate(employee$SalesAmount, 
                  by=list(employee$Color), 
                  FUN=sum)
print(output)

barplot(output$x, 
        main = "Sales By Product Color",
        xlab = "Product Colors",
        ylab = "Sales",
        names = output$Group.1)
Assign Names 3

Change Colors of barplot

In this example, we change the bar chart colors using col argument and border colors using border argument.

# Changing Colors of lines and Borders Example
getwd()

employee <- read.csv("Products.csv", TRUE, sep = ",", 
                     na.strings = TRUE)
output <- aggregate(employee$SalesAmount, 
                  by=list(employee$Color), 
                  FUN=sum)
print(output)

barplot(output$x, 
        main = "Sales By Product Color",
        xlab = "Product Colors",
        ylab = "Sales",
        names = output$Group.1,
        col = "chocolate",
        border = "red")
Change the Color using col 4

TIP: To assign different border colors to use a Vector of colors. For example, border = c(“red”, “black”, “green”, …)

Horizontal Bar Chart in R Programming

In this example, we change the default vertical into a horizontal bar chart using horiz argument. We also use the density argument in the R barplot to change the bar density.

getwd()

employee <- read.csv("Products.csv", TRUE, sep = ",", 
                     na.strings = TRUE)
output <- aggregate(employee$SalesAmount, 
                  by=list(employee$Color), 
                  FUN=sum)
print(output)

barplot(output$x, 
        main = "Sales By Product Color",
        xlab = "Product Colors",
        ylab = "Sales",
        names = output$Group.1,
        col = "chocolate",
        horiz = TRUE,
        density = 80,
        border = "red")
Barplot in R Programming 5

Create Stacked Barplot in R Programming

Let us see how to create a stacked barplot and how to add Legend to the bar chart using the legend function.

The following count statement creates a table with records of sales amount and color. Here, column values are unique colors, and row values are unique sales amounts.

Next, we create an R stacked bar chart using the above-specified table.

getwd()

employee <- read.csv("Products.csv", TRUE, sep = ",", na.strings = TRUE)
count <- table(employee$SalesAmount, employee$Color)
count
cols = c("Black", "Blue", "brown", 
         "green", "Red", "gray", "White", "Yellow")
barplot(count, col = cols)

legend("topright", 
       c("Black", "Blue", "Multi", "No Color", 
         "Red", "Silver", "White", "Yellow"), 
       fill = cols )
stacked Bar chart in R Programming 6

Create Juxtaposed Barplot in R Programming

In this example, we create a juxtaposed barplot using beside argument.

# Juxtaposed Example
getwd()

employee <- read.csv("Products.csv", TRUE, sep = ","
                     , na.strings = TRUE)
count <- table(employee$SalesAmount, employee$Color)
count
cols = c("Black", "Blue", "brown", 
         "green", "Red", "gray", "White", "Yellow")
barplot(count, col = cols, beside = TRUE)

legend("topright", 
       c("Black", "Blue", "Multi", "No Color", 
         "Red", "Silver", "White", "Yellow"), 
       fill = cols )
Juxtaposed Example 7

Use Matrix to create Barplot in R Programming

In this example, we create a bar chart using Matrix values.

# Create using Matrix Example

vec <- c(4, 9, 11, 12, 17, 6, 9, 23, 2, 15, 1, 8 ) 
values <-  matrix(vec, nrow = 3, ncol = 4)
values
barplot(values, col = c("brown", "chocolate", "yellow"))
Barplot in R Programming 8

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