What is is.vector() Function in R

A vector is a data structure that stores multiple values of the same type. 

The is.vector() function does not merely check whether an R object is a vector. Instead, it checks whether an input object is a vector with no attributes other than names.

Syntax

is.vector(obj, mode)

Parameters

Return value

• It returns TRUE If the input object is a vector with no attributes other than names.
  
• It returns FALSE If the object has additional attributes (such as dimensions or class) or is not a vector.

Type of modes

Here are the possible values of the “mode” argument:

Atomic modes

1. numeric
   
2. logical
   
3. character
   
4. complex

Other modes

1. list
2. expression

Special modes

1. any

Without “mode” argument

Let’s create atomic vectors of different types and check if those are vectors or not.

# Creating a numeric vector
numeric_vector <- c(1, 2, 3)

# Checking if it's a numeric vector
is.vector(numeric_vector) # Output: TRUE

# Creating a character vector
character_vector <- c("apple", "banana", "cherry")

# Checking if it's a character vector
is.vector(character_vector) # Output: TRUE

# Creating a logical vector
logical_vector <- c(TRUE, FALSE)

# Checking if it's a logical vector
is.vector(logical_vector) # Output: TRUE

# Creating a complex vector
complex_vector <- c(1 + 9i, 2 + 1i)

# Checking if it's a complex vector
is.vector(complex_vector) # Output: TRUE

If you apply the is.vector() function to atomic vectors that do not have additional attributes other than names, it will return TRUE.

However, if an atomic vector has additional attributes (For example, “class”), this function will return FALSE.

numeric_vector <- c(1, 2, 3)


attr(numeric_vector, "class") <- "hello"


is.vector(numeric_vector) # Output: FALSE

With “mode” argument

If you create a “logical” vector and pass that vector with mode argument as “logical”, the function will return TRUE. However, if you create a logical vector and pass the mode argument as “numeric” or any type other than “logical”, it will return FALSE.

Ensure that your mode argument aligns with your data type or doesn’t pass at all if not needed.

numeric_vector <- c(11, 21, 3.14, 51)
is.vector(numeric_vector, mode = "numeric") # Output: TRUE

numeric_vector_two <- c(11, 21, 3.14, 51)
is.vector(numeric_vector_two, mode = "complex") # Output: FALSE

logical_vector <- c(TRUE, FALSE, TRUE)
is.vector(logical_vector, mode = "logical") # Output: TRUE

logical_vector_two <- c(TRUE, FALSE, TRUE)
is.vector(logical_vector_two, mode = "numeric") # Output: FALSE

character_vector <- c("apple", "banana", "cherry")
is.vector(character_vector, mode = "character") # Output: TRUE

character_vector_two <- c("apple", "banana", "cherry")
is.vector(character_vector_two, mode = "logical") # Output: FALSE

complex_vector <- c(1 + 2i, 3 - 4i)
is.vector(complex_vector, mode = "complex") # Output: TRUE

complex_vector_two <- c(1 + 2i, 3 - 4i)
is.vector(complex_vector_two, mode = "character") # Output: FALSE

Example of “any” mode

The “any” mode means the function will check a vector of any data type. It doesn’t matter if it’s numeric, character, logical, or complex. As long as it’s a vector, it will return TRUE.

numeric_vector <- c(11, 21, 31)

is.vector(numeric_vector, mode = "any") # Output: TRUE

character_vector <- c("kb", "kl", "yv")

is.vector(character_vector, mode = "any") # Output: TRUE

List and expression

A list is technically a vector because R considers lists recursive vectors, which allow nested elements and are one-dimensional structures that may contain different data types.

main_list <- list(c(1, 2), c("Krunal", "Ankit"))

is.vector(main_list) # TRUE

Let’s evaluate an expression.

expression = "iconic1010"

is.vector(expression) # Output: TRUE

We found practically that R counts the list and expression as a “vector” without attributes other than names.

Data Frames

Data frames are complex data structures consisting of rows and columns.

If you directly check on data frames, is.vector() function returns FALSE. The data frame itself is not a vector.

df <- data.frame(a = c(1, 2), b = c("hello", "world"))

is.vector(df, mode = "any") # Output: FALSE

However, if you check for the data frame’s columns, this function will return TRUE because columns are vectors in the data frame.

df <- data.frame(a = c(1, 2), b = c("hello", "world"))

is.vector(df$a, mode = "any") # Output: TRUE
is.vector(df$b, mode = "any") # Output: TRUE

That’s all!