Ploting with qplot

Overview

Teaching: 10 min
Exercises: 0 min

Questions

• How to quick plot in R using ggplot2 package

Objectives

• Learn professional plotting tool in R using qplot

• Learn multiple way to use qplot

What is qplot

• qplot stands for quick plot in ggplot2.
• It is similar to basic plot in R but with ggplot 2’s standard

In this episode, we gonna learn how to quickly visualize data using qplot

Basic qplot: Scatter plot

• Plots are made of aes (size, shape, color) and geom (points, lines)
• Look for data in frame (or from parent directory)

  qplot(Sepal.Length, Sepal.Width, data=iris)
  

• Add aesthetic (shape, color)

  qplot(Sepal.Length, Petal.Length, data=iris,
      color=factor(Species),
      shape=factor(Species)) #aesthetic
  

  

• Add geom (points, lines)

  qplot(Sepal.Length, Petal.Length, data=iris,
      geom=c("point","smooth")) #geometry
  

  

• Linear Fitting

  qplot(Sepal.Length, Petal.Length, data=iris, color=Species,
      geom=c("point","smooth"),method="lm")
  

  

Basic qplot: Histogram

qplot(Sepal.Length,fill=Species, data=iris)
qplot(Sepal.Length,data=iris,geom="density")
qplot(Sepal.Length,data=iris,geom="density",
      color=Species)

Basic qplot: Facets

qplot(Sepal.Length,Petal.Length,facets=.~Species, data=iris)

Key Points

• ggplot2

• qplot