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Explain Character Vector in R?

Naveen Nelamali
r character vector

Character Vector in R is a vector of a type character that is used to store strings and NA values. In this article, I will explain what is a character vector, how to use it with methods like character(), as.character() and is.character() functions.

What is a Character Vector in R?

A vector where each element has only alphabet characters (a-z or A-Z) of any size is a character vector. For example, c('ABC','abc','AbC','12AB') is a character vector of length 3. One can create a character vector using c() or character() functions.

Following are the most used methods of character vector in R and their usage.

Character Vector FunctionsUsage
character()character(length = 0)
is.character()is.character(x)
as.character()as.character(x, …)
nchar()
Character Vector Functions

Character vector can have the following values

1. character()

character() function is used to create a character vector in R of a specified length. All elements of the R vector will contain the empty string “”. By default, not using a length creates an empty vector.

Following is the syntax of the character() vector.


# Syntax of character
character(length = 0)

The following example initializes a vector with 5 empty strings.


# Usage of character()
v <- character(4)
print(v)
length(v)

# Output
#[1] "" "" "" "" ""
#[1] 5

2. Create Character Vector

To create a vector use c() function and to create a character vector use string elements as values. Once the vector is created, check the type of the vector using typeof() function.


# Create vector
v <- c('a','ABC','bc','A',NA)
print(v)
typeof(v)

# Output
#[1] "a"   "ABC" "bc"  "A"   NA   
#[1] "character"

3. is.character()

To check if the vector is of type character use is.character() function. This function takes a vector as an argument and returns TRUE for a character vector otherwise FALSE.


# Check if vector is character type
is.character(v)

# Output
# TRUE

# Numeric vector
n <- c(1,2,3)
is.character(n)

# Output
# FALSE

4. as.character()

as.character() function is used to convert the vector to the character type. This function takes the values of non-character and creates a character vector.


# Convert elements to character vector
v <- as.character(1,2,3)
typeof(v)

# Output
#[1] "character"

5. ncahr()

The nchar() function is used to get the length of each element of the character vector in R. For the NA element it returns NA as length.


# Get length of each element.
v <- c('a','ABC','bc','A',NA)
nchar(v)

# Output
#[1]  1  3  2  1 NA

6. Equal Condition

When you check if a value is equal in a vector by an equal condition, it returns a logical vector representing TRUE if a value is equal otherwise represents FALSE.


res <- v == 'a'
print(res)

# Output
[1]  TRUE FALSE FALSE FALSE    NA

7. Conclusion

In this article, I have explained what is character vectors in R, what character functions, and how to use them. character() function initialized character vector with an empty string. is.character() check if a vector is a character type. as.character() returns a character vector for non char elements. You can find the complete example from this article at Github R Programming Examples Project.

References

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