You can use the following methods to suppress warnings in R:

Method 1: Suppress Warnings on Specific Line

suppressWarnings(one line of code)

Method 2: Suppress Warnings Globally

suppressWarnings({

several lines of code
just a bunch of code
lots and lots of code

})

The following examples show how to use each method in practice with the following code, which produces two warning messages:

#define character vector
x <- c('1', '2', '3', NA, '4', 'Hey')

#convert to numeric vector
x_numeric <- as.numeric(x)

#display numeric vector
print(x_numeric)

Warning message:
NAs introduced by coercion 
[1]  1  2  3 NA  4 NA

#define two vectors
a <- c(1, 2, 3, 4, 5)
b <- c(6, 7, 8, 9)

#add the two vectors
a + b

[1]  7  9 11 13 11
Warning message:
In a + b : longer object length is not a multiple of shorter object length

Method 1: Suppress Warnings on Specific Line

We can wrap the suppressWarnings() function around the as.numeric() function to suppress only the first warning in the code:

#define character vector
x <- c('1', '2', '3', NA, '4', 'Hey')

#convert to numeric vector
suppressWarnings(x_numeric <- as.numeric(x))

#display numeric vector
print(x_numeric)

[1]  1  2  3 NA  4 NA

#define two vectors
a <- c(1, 2, 3, 4, 5)
b <- c(6, 7, 8, 9)

#add the two vectors
a + b

[1]  7  9 11 13 11
Warning message:
In a + b : longer object length is not a multiple of shorter object length

Notice that the first warning message no longer appears but the second warning message still appears.

Method 2: Suppress Warnings Globally

We can wrap the suppressWarnings({}) function around the entire chunk of code to suppress all warnings globally:

suppressWarnings({

#define character vector
x <- c('1', '2', '3', NA, '4', 'Hey')

#convert to numeric vector
suppressWarnings(x_numeric <- as.numeric(x))

#display numeric vector
print(x_numeric)

[1]  1  2  3 NA  4 NA

#define two vectors
a <- c(1, 2, 3, 4, 5)
b <- c(6, 7, 8, 9)

#add the two vectors
a + b

[1]  7  9 11 13 11

})

Notice that we don’t receive any warnings this time because we wrapped the suppressWarnings({}) function around the entire chunk of code.