R Language: A Quick Reference – II

R Programming: A Quick Reference

R language: A Quick Reference is about learning R Programming with a short description of the widely used commands. It will help the learner and intermediate user of the R Programming Language to get help with different functions quickly. This Quick Reference is classified into different groups. Let us start with R Language: A Quick Reference – II.

This R Language: A Quick Reference contains R commands about creating vectors, matrices, lists, data frames, arrays, and factors. It also discusses setting the different properties related to R language data types.

Creating Vectors in R Language

The creation of a row or column vector in the R Language is very important. One can easily create a vector of numbers, characters/ strings, complex numbers, and logical values, and can concatenate the elements.

R commandShort Description
c(a1, a2, …, an)Concatenates all $n$ elements to a vector
logical(n)Creates a logical vector of length $n$ (containing false)
numeric(n)Creates a numeric vector of length $n$ (containing zeros)
character(n)Creates a character vector of length $n$ (containing an empty string)
complex(n)Creates a complex vector of length $n$ (containing zeros)

Creating Lists in R Language

Creating Lists in R is important as it can store different types of data and even lists. A vector can also be used to create a list of $k$ elements.

R CommandShort Description
list(e1, e2, … ek)Combines all $k$ elements as a list
vector(k, “list”)Creates a list of length $k$ (the elements are all NULL)

Creating Matrices in R Language

Two-dimensional data can be created using the matrix command in R.

R CommandShort Description
matrix(x, nr = r, nc = c)Creates a matrix from $x$ (column as major order)
matrix(x, nr = r, nc = c)Creates a matrix from $x$ (row as major order)

Creating Factors in R Language

To create categorical variables, R has a concept of factors as variables. All factors have levels that may have ordered factors.

R CommandShort Description
factor(x)Creates a factor from the values of variable $x$
factor(x, levels = 1)Creates a factor with the given level set from the values of the variable $x$
ordered(x)Creates an ordered factor with the given level set from the values of the variable $x$
levels(x)Gives the levels of a factor or ordered factor
levels(x) = vSet or reset the levels of a factor or ordered factor

Creating a Data Frame in R Language

A data frame is a tabular data format used for statistical data analysis. The format of the data is like data entered in spreadsheets for data analysis.

R CommandShort Description
data.frame(n1=x1, n2=x2, ….)Creates a data frame

R Language Data Type Properties

Every data object has different properties. These properties can be used to find out the number of rows in a vector or matrix, the number of columns, names of rows and columns of a matrix or data frame.

R CommandShort Description
length(x)Gives the number of elements in a variable $x$
mode(x)Tells about the data type of the variable $x$
nrow(x)Displays the number of rows of a vector, array, or data frame $x$
ncol(x)Displays the number of columns (variable) of a vector, array, or data frame $x$
dim(x)Displays the dimension (number of rows and columns) of a matrix, data frame, array, or list $x$
row(x)Matrix of row indices for matrix-like object $x$
col(x)Matrix of column indices for matrix-like object $x$
rownames(x)Get the row names of the matrix-like object $x$
rownames(x)=vSet the row names of the matrix-like object $x$ to $v$
colnames(x)Get the column names of the matrix-like object $x$
colnames(x)=vSet the column names of the matrix-like object $x$ to $v$
dimnames(x)Get both the row and column names (in a matrix, data frame, or list)
dimnames(x)=list(rn, cn)Set both the row and column names
names(x)Gives the names of $x$
namex(x)=vSets or resets the names of $x$ to $v$
names(x)=NULLremoves the names from $x$
row.names(df)Gives the observation names from a data frame
row.names(df)=vSets or resets the observation names of a data frame
names(df)Gives the variables names from a data frame
names(df)=vSets or resets the variable names of a data frame

R Language: A Quick Reference – I

R Language: A Quick Reference – II
Scroll to top
x  Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
Shield Security