Vectors

Here, we will learn what vectors are in R and how to create them.

We'll cover the following

A Vector is a basic data structure in R. It contains elements of the same type at each index. The data types can be

  • Logical
  • Integer
  • Numeric
  • Character
  • Complex

Creating Vectors

The keyword vector() is used to create a vector of a fixed type and fixed length.

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vector ("numeric", 5) # numeric vector with O at every index
vector ("complex", 5) # complex vector with O+0i at every index
vector ("logical", 5) # logical vector with FALSE at every index
vector ("character", 5) # character vector with "" at every index

Using this method every index will now have a value of zero, FALSE, null string or something equivalent to nothing for the specified data type.

A vector’s type can be checked with typeof(), and the number of elements in the vector can be checked with length().

We have already discussed these but let’s see their usage with vectors again.

myNumericVector <- vector ("numeric", 5)
typeof(myNumericVector)
myComplexVector <- vector ("complex", 5)
typeof(myComplexVector)
Example of typeof() function with vectors

Now, what if we do not want our vector to be initialized by nothing but want to make specific initializations?

Creating Vectors by Concatenation

The c() function can be used to create vectors of objects by concatenating things together. By using this function, we can directly specify the content of the vector.

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myRealNumericVector <- c(1, 2, 3, 4)              # numeric
myDecimalNumericVector <- c(0.1, 0.2, 0.3, 0.4)   # numeric
myLogiacalVector <- c(TRUE, FALSE)                # logical
myCharacterVector <- c("a", "b", "c")             # character
myIntegerVector <- 1:10                           # integer
myComplexVector <- c(1+1i, 2+2i)                  # complex

You can also make a vector with just one value. R saves single values as a vector of length 1.

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myVector <- 5
is.vector(myVector)
length(myVector)

In the above code snippet, the function is.vector() returns true if the variable is a vector and false otherwise.

Here is.vector() is a built-in R function.

Converting Vectors to Strings

Suppose we want to convert a vector of strings into a single string. We can do that by using paste(). We can use the argument collapse with paste() to concatenate strings in a vector and removing the quotation marks between them.

The collapse parameter specifies the character to be used between individual vector elements.

myVector <- c("learning", "is", "fun")
paste(myVector, collapse = ".")
paste() with collapse = "." argument

Inserting Elements in a Vector

We can add elements in a vector using the same c() method.

By using c() we can concatenate two vectors, in addition to inserting a number into a vector.

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myVector <- c(1, 2, 3, 4)           
cat("Original Vector: ")   
print(myVector)
myVector <- c(0, myVector) 
cat("Appending 0 at the start of the vector: ")
print(myVector)
myVector <- c(myVector, 5) 
cat("Appending 5 at the end of the vector: ")
print(myVector)
tempVector <- c(6, 7, 8)
myVector <- c(myVector, tempVector)
cat("Appending another vector at the end of the original vector: ")
print(myVector)

Accessing and Modifying Vectors

We can fetch an element at a specific index in a vector by using the vector’s name with square brackets [] around the specified index.

vectorName[<index>]

Indexing starts at 11, which means that the first element of the vector is at index 1.

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myVector <- c(0, 1, 2, 3)           
print(myVector[1])

We can also modify the value at a specific index of the vector.

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myVector <- c(0, 1, 2, 3)     
myVector[1] <- 5      
print(myVector[1])