Tutorial of Barplot in Base R Programming Language

Veer Kumar
Last Updated On April 4, 2022
Visualization

Table of Contents

Introduction

Base R language can be used to create good visualizations easily out of the box. In this article, we’ll go through the tutorial for creating bar plot in base R programming language. First, the syntax of the barplot() function in R will be explained, and then we will go through different examples of creating barplot with this function.

Syntax of Bar Plot barplot() function in R

Following is the basic syntax of barplot() function in R with some important arguments. The detailed syntax can be found here.

barplot(height, xlab, ylab, main, names.arg, col)

height – It is a vector or matrix that contains the value used for creating the bar of the plot.
xlab – It sets the label for x axis.
ylab – It sets the label for y axis.

main – It set the title of the barplot.
names.arg – It sets the names under each bar.
col – It is used for assigning colors to the bar plot.

Examples of Barplot in R Language

Loading Dataset

The CO2 dataset is built into R that contains the findings of a study on grass cold tolerance. CO2 absorption rate and concentration levels were measured in grass samples from two regions of Quebec and Mississippi, which were grown in either a chilled or nonchilled environment.

This dataset is loaded into the dataframe df as shown below and some of its rows are displayed. This dataset will be

In [1]:

df<-(CO2)
head(df)

Out[1]:

Plant	Type	Treatment	conc	uptake
Qn1	Quebec	nonchilled	95	16.0
Qn1	Quebec	nonchilled	175	30.4
Qn1	Quebec	nonchilled	250	34.8
Qn1	Quebec	nonchilled	350	37.2
Qn1	Quebec	nonchilled	500	35.3
Qn1	Quebec	nonchilled	675	39.2

In [2]:

data <-df[1:10, "conc"]

Example – 1: Simple Barplot in Base R Language

In the below example, we are plotting the basic bar plot in base R by passing the subsetted dataset into the barplot function.

In [3]:

barplot(data)

Out[3]:

Example – 2: Horizontal Barplot in Base R Language

We can create the horizontal bar plot in base R by passing the horiz=TRUE argument as shown in the below example.

In [4]:

# Horizontal bar plot
barplot(data, horiz = TRUE)

Out[4]:

Example – 3: Coloring the Barplot with Single Color

To color the barplot, just use the col parameter and pass the specific color value to fill the plot.

In [5]:

barplot(data, col = "#CD534CFE")

Out[5]:

Example – 4: Coloring the Barplot with Multiple Colors

The coloring of the barplot with multiple colors can be done as shown in the below example.

In [6]:

barplot(data, col = c("#999999", "#E69F00", "#56B4E9"))

Out[6]:

Example – 5: Coloring the Border of Barplot

The border of the barplot in R language can be colored with ‘border’ parameter. In the below example. we have colored the barplot with white so that the border color is more prominent.

In [7]:

barplot(data, col = "white", border = "steelblue")

Out[7]:

Example – 6: Labeling the Barplot in R

To customize the labeling of our barplot we use the names. arg parameter and pass the desired labels into it.

In [8]:

barplot(data,col ='lightgreen', names.arg = c("A", "B", "C","D",'E','F','G','H','I','J'))

Out[8]:

Example – 7: Adding Titles to Barplot in R

The title of the barplot can be added with ‘main’ parameter and the x & y title can be added with ‘xlab’ and ‘ylab’ parameters respectively.

In [9]:

barplot(data, main = "Monthly Temperatures",
        xlab = "Months", ylab = "Temperatures", col = c("yellow", "orange", "pink"))

Out[9]:

Example – 7: Stacked Barplot with Colors and Legend

To create the stacked barplot in R, first of all, we apply the table function on Plant and Treatment columns to create a cross table. And then we pass this data to barplot() function as shown below to generate the stacked bar plot.

In [10]:

counts <- table(df$Plant, df$Treatment)
barplot(counts, main="Distribution by plant and treaement facility",
  xlab="Temp", col=rainbow(12),
  legend = rownames(counts))

Out[10]:

Example – 8: Grouped Bar Plot in R

First of all, let us use tapply function to create group summaries. The output of this is shown below.

In [11]:

summary_data <- tapply(df$uptake, list(type = df$Type,
                                       treatment = df$Treatment),
                       FUN = mean, na.rm = TRUE)

In [12]:

summary_data

Out[12]:

	nonchilled	chilled
Quebec	35.33333	31.75238
Mississippi	25.95238	15.81429

Let us now use the above data to create a grouped bar chart as shown below.

In [13]:

barplot(summary_data, xlab = "Treatment type",
        main = "Uptake mean",
        col = rainbow(2),
        beside = TRUE,
        legend.text = rownames(summary_data),
        args.legend = list(title = "Type", x = "topright",
                           inset = c(-0.1,-0.17)))

Out[13]:

Example – 9: Applying Spacing in Grouped Barplot

To change the space between bars, in the case of several groups, we can set a two-element vector where the first element is the space between bars of each group (0.4) and the second the space between groups(2.5), as demonstrated below.

In [14]:

barplot(summary_data,
        main = "Grouped barchart space",
        xlab = "Treatment type", ylab = "Frequency",
        col = c("brown", "green"),
        legend.text = rownames(summary_data),
        beside = TRUE,
        space = c(0.4, 2.5))

Out[14]:

Veer Kumar

I am passionate about Analytics and I am looking for opportunities to hone my current skills to gain prominence in the field of Data Science.
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