barplot using ggplot2
barplot

Introduction

Let’s begin learning about how to plot barplot in R using ggplot2

Do you want to learn about how to make a barplot for any categorical variable using ggplot2 in R? If yes,then this is the right page for you.Follow this tutorial given below

Importing libraries

Let’s import the ggplot2 library which is needed for ggplot visualization

library(ggplot2)

Reading data set

Let’s import the data set named “diamonds” into the dataframe named DataFrame

DataFrame<-diamonds

Looking at data 

Let’s check the str of the data set

str(DataFrame)
## Classes 'tbl_df', 'tbl' and 'data.frame':    53940 obs. of  10 variables:
##  $ carat  : num  0.23 0.21 0.23 0.29 0.31 0.24 0.24 0.26 0.22 0.23 ...
##  $ cut    : Ord.factor w/ 5 levels "Fair"<"Good"<..: 5 4 2 4 2 3 3 3 1 3 ...
##  $ color  : Ord.factor w/ 7 levels "D"<"E"<"F"<"G"<..: 2 2 2 6 7 7 6 5 2 5 ...
##  $ clarity: Ord.factor w/ 8 levels "I1"<"SI2"<"SI1"<..: 2 3 5 4 2 6 7 3 4 5 ...
##  $ depth  : num  61.5 59.8 56.9 62.4 63.3 62.8 62.3 61.9 65.1 59.4 ...
##  $ table  : num  55 61 65 58 58 57 57 55 61 61 ...
##  $ price  : int  326 326 327 334 335 336 336 337 337 338 ...
##  $ x      : num  3.95 3.89 4.05 4.2 4.34 3.94 3.95 4.07 3.87 4 ...
##  $ y      : num  3.98 3.84 4.07 4.23 4.35 3.96 3.98 4.11 3.78 4.05 ...
##  $ z      : num  2.43 2.31 2.31 2.63 2.75 2.48 2.47 2.53 2.49 2.39 ...

Barplot using ggplot 

Let’s choose the cut variable in the dataset.It is categorical or factor variable
and let’s visualize it in barplot

ggplot(data = DataFrame)+geom_bar(aes(x =cut),
                                   color="orange",
                                   fill="blue",
                                   alpha=0.5
                   )+
  scale_x_discrete()+
  scale_y_continuous(name="Frequency of diamonds in each cut cateogory")+
  theme_bw()
barplot using ggplot2
barplot

Meaning of arguments in ggplot function:

Above is the format which you can use for any bar plot visualization
Meanings of some parameters and functions are as follows:

Functions used are :

  • ggplot() is basic function which is used in every visualization
  • This takes in data argument which is the name of dataframe
  • geom_bar is used for plotting barplot.This takes in aes() function
    and other arguments
  • scale_x_discrete is used for customizing the x axis(categorical or discrete variable)
  • theme_bw() is used for customizing the plot background

Parameters used are :

  • fill=used for color used in filling the rectangular boxes of barplot
  • color=used for color of edges of bar plot
  • alpha=used for transparency in plot.Very useful when you want to plot one
    over another