1 QUICK START TO R PROGRAMMING

Author

Yi Wang

1.1 1-minture `R` Programming Introduction

Variables: To create a variable, use the assignment operator <-. For example,

Code

x <- 5

Data Structures: R supports various data structures such as vectors, matrices, arrays, lists, and dataframes. For instance, you can create a vector using c() like

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my_vector <- c(1, 2, 3, 4, 5)

To index the second element of my_vector, use [] operator:

Code

my_vector[2]

[1] 2

The output after running the code my_vector[2] is displayed as [1] 2, where [1] indicates the first line of the output, and 2 is the value of my_vector[2].

To print a formatted output, use the built-in function cat to concatenate strings enclosed in double quotes ""(or equivalently single quotes ' '). Note "\n" represents a newline feed. For example:

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cat("The first element in my_vector is:", my_vector[1], "\n")

The first element in my_vector is: 1

Functions: Functions in R are defined using the function() keyword. For example, you can create a function as follows:

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my_sum <- function(arg1, arg2) {
  # function body
  return(arg1 + arg2)  #return the sum of arg1 and arg2
}

Code comment: A code comment starts with #. A comment line will not affect your code. When a R-code is executed, a comment line will be ignored by the R-code interpreter. When you are following along with the code in this manual, you do not need to type the line starting with #. They are provided to interpret the codes.

Control Structures: R supports typical control structures like if-else statements, for loops, while loops, etc.

Packages: R’s functionality can be extended through packages. You can install packages using the install.packages("package_name") function and load them using the library("package_name") function.

Data Manipulation and Analysis: R provides powerful tools for data manipulation and analysis. Packages like dplyr and ggplot2 are commonly used for data manipulation and visualization, respectively.

Help: to access the help document, type in the R-console: ?function_name or help(function_name). For example, ?mean or help(mean).

1.1 1-minture R Programming Introduction

1.1 1-minture `R` Programming Introduction