You can use the built-in tolower() function in R to convert strings to lowercase.
#convert string to lowercase
tolower(string_name)
The following examples show how to use this function in practice.
Example 1: Convert a Single String to Lowercase
The following code shows how to convert a single string to lowercase in R:
#create string my_string <- 'THIS IS A SENTENCE WITH WORDS.' #convert string to all lowercase tolower(my_string) [1] "this is a sentence with words."
Note that the tolower() function converts all characters in a string to lowercase
Example 2: Convert Each String in Column to Lowercase
The following code shows how to convert every string in a column of a data frame to lowercase:
#create data frame
df <- data.frame(team=c('Mavs', 'Nets', 'Spurs'),
points=c(99, 94, 85),
rebounds=c(31, 22, 29))
#view data frame
df
team points rebounds
1 Mavs 99 31
2 Nets 94 22
3 Spurs 85 29
#convert team names to lowercase
df$team <- tolower(df$team)
#view updated data frame
df
team points rebounds
1 mavs 99 31
2 nets 94 22
3 spurs 85 29
Example 3: Convert Strings in Multiple Columns to Lowercase
The following code shows how to convert strings in multiple columns of a data frame to lowercase:
#create data frame
df <- data.frame(team=c('Mavs', 'Nets', 'Spurs'),
conf=c('WEST', 'EAST', 'WEST'),
points=c(99, 94, 85))
#view data frame
df
team conf points
1 Mavs WEST 99
2 Nets EAST 94
3 Spurs WEST 85
#convert team and conference to lowercase
df[c('team', 'conf')] <- sapply(df[c('team', 'conf')], function(x) tolower(x))
#view updated data frame
df
team conf points
1 mavs west 99
2 nets east 94
3 spurs west 85
Additional Resources
The following tutorials explain how to perform other common tasks related to strings in R:
How to Use str_split in R
How to Use str_replace in R
How to Convert a Vector to String in R