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Introduction to R: Glossary

Key Points

Before we Start
  • Use RStudio to write and run R programs.

  • Use install.packages() to install packages (libraries).

Introduction to R
  • Use the assignment operator <- to assign values to objects. You can now manipulate that object in R

  • R contains a number of functions you use to do something with your data. Functions automate more complicated sets of commands. Many functions are predefined, or can be made available by importing R packages

  • A vector is a sequence of elements of the same type. All data in a vector must be of the same type–character, numeric (or double), integer, and logical. Create vectors with c(). Use [ ] to subset values from vectors.

Starting with Data
  • Use read.csv to read tabular data in R.

  • Use factors to represent categorical data in R.

Data cleaning & transformation with dplyr
  • Use the dplyr package to manipulate dataframes.

  • Use select() to choose variables from a dataframe.

  • Use filter() to choose data based on values.

  • Use group_by() and summarize() to work with subsets of data.

  • Use mutate() to create new variables.

Data Visualisation with ggplot2
  • ggplot2 is a flexible and useful tool for creating plots in R.

  • The data set and coordinate system can be defined using the ggplot function.

  • Additional layers, including geoms, are added using the + operator.

  • Boxplots are useful for visualizing the distribution of a continuous variable.

  • Barplot are useful for visualizing categorical data.

  • Faceting allows you to generate multiple plots based on a categorical variable.

Glossary

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