R Cheat Sheet For Everyone

R is a powerful programming language used for data analysis and statistical computing. Here is a quick reference guide to get you started with R programming.

Basic Syntax:

• Comments start with the “#” symbol
• Assignment operator is “<-“
• Function calls use parentheses, e.g. mean(x)
• “print()” function can be used to display results
• Use “?” before a function to get help, e.g. ?mean

Data Types:

• Numeric: numbers with decimal places, e.g. 3.14
• Integer: whole numbers, e.g. 5
• Character: text, e.g. “hello”
• Factor: categorical data, e.g. “male” or “female”
• Logical: binary values, either TRUE or FALSE

Vectors:

• A vector is a collection of values with the same data type
• Creation of vectors using c(), e.g. c(1,2,3)
• Use “[]” to access elements of a vector, e.g. x[2]
• Use “length()” to get the number of elements in a vector

Matrices:

• A matrix is a 2-dimensional vector with rows and columns
• Creation of matrices using matrix(), e.g. matrix(1:9, ncol=3)
• Use “[row, col]” to access elements of a matrix, e.g. m[2,3]
• Use “dim()” to get the dimensions of a matrix

DataFrames:

• A data frame is a 2-dimensional data structure with rows and columns
• Creation of data frames using data.frame(), e.g. data.frame(x=1:5, y=6:10)
• Use “$” to access columns of a data frame, e.g. df$x
• Use “nrow()” and “ncol()” to get the number of rows and columns

Reading Data:

• Use read.csv() to read csv files, e.g. read.csv(“data.csv”)
• Use read.table() to read other types of files, e.g. read.table(“data.txt”, sep=”\t”)

Data Manipulation:

• Use “head()” and “tail()” to view the first and last few rows of a data frame
• Use “subset()” to extract a subset of a data frame based on conditions, e.g. subset(df, x > 3)
• Use “merge()” to combine two data frames based on common columns

Plotting:

• Use “plot()” to create basic plots, e.g. plot(x, y)
• Use “hist()” to create histograms, e.g. hist(x)
• Use “boxplot()” to create box plots, e.g. boxplot(x)
• Use “barplot()” to create bar plots, e.g. barplot(x)

Statistics:

• Use “mean()” to calculate the mean of a vector, e.g. mean(x)
• Use “median()” to calculate the median of a vector, e.g. median(x)
• Use “sd()” to calculate the standard deviation of a vector, e.g. sd(x)
• Use “summary()” to get a summary of a data frame, e.g. summary(df)