# Case conversion of a String in R Language – toupper(), tolower(), casefold() and cartr() Function

• Last Updated : 23 Dec, 2021

In this article, we are going to see case conversion of a string in R Programming Language.

### R – toupper()

toupper() function in R Language is used to convert the lowercase letters to uppercase.

Syntax: toupper(x)

Parameters:

x: character vector

Example:

## R

 `# R program to illustrate``# uppercase of vectors` `# Create example character string``x <- ``"GeeksforGeeks"`               `toupper``(x)` `print``(x)`

Output:

`GEEKSFORGEEKS`

Here in the above code, we have converted an example vector of characters to uppercase characters.

### R – tolower() Function

tolower() function is used to convert the uppercase letters to lowercase.

Syntax: tolower(x)

Parameters:

x: character vector

Example:

## R

 `# R program to illustrate``# uppercase of vectors` `# Create example character string``x <- ``"GeeksforGeeks"``tolower``(x)` `print``(x)`

Output:

`geeksforgeeks`

### R – casefold() Function

casefold() function takes character vector and boolean value as argument. This boolean value decides the conversion to upper and lower case.

Syntax: casefold(x, upper)

Parameters:

• x: Character Vector
• upper: Boolean value for case conversion

Example 1:

## R

 `# Create example character string``x <- ``"GeeksforGeeks"` `# Convert to lower case letters``x <- ``casefold``(x, upper = ``FALSE``)` `print``(x)           `

Output:

`"geeksforgeeks"`

Here in the above code, the boolean value for the upper is set to be FALSE to convert the character vector to lowercase.

Example 2:

## R

 `# Create example character string``x <- ``"GeeksforGeeks"` `# Convert to upper case letters``casefold``(x, upper = ``TRUE``)` `print``(x)           `

Output:

`"GEEKSFORGEEKS"`

Here in the above code, the boolean value for the upper is set to be TRUE to convert the character vector to Uppercase.

### R – cartr() Function

cartr() function in R Programming is used when we have to make some characters to upper case and some to lower case.

Syntax: cartr(x, old, new)

Parameters:

• x: character vector
• old: a character string specifying the characters to be translated.
• new: a character string specifying the translations

Example:

## R

 `# Create example character string``x <- ``"GeeksforGeeks"` `# Translate to upper and lower case``chartr``(old = ``"Geeks"``, new = ``"GeEkS"``, x)   `

Output:

`"GeEkSforGeeks"`

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