How to Use make.names Function in R (With Examples)

You can use the make.names function in R to create syntactically valid names out of character vectors.

This function uses the following basic syntax:

make.names(names, unique = FALSE)

where:

• names: Character vector to be coerced to syntactically valid names.
• unique: Whether or not to create unique names. Default is FALSE.

The following examples show how to use this function in different scenarios.

Example 1: Create Valid Names for Vector

Suppose we have the following vector of numeric values:

#create vector of numeric values
numeric_values #create syntactically valid names from numeric values
make.names(numeric_values)

[1] "X1" "X1" "X4" "X7" "X8"

R defines “valid names” as names that start with a character or dot.

Thus, to convert each of the numeric values in the vector to a valid name, R simply adds an “X” in front of each value.

Note that two of the names (“X1”) are the exact same.

To force the names to be unique, we can specify unique=TRUE:

#create vector of numeric values
numeric_values #create syntactically valid names from numeric values
make.names(numeric_values, unique=TRUE)

[1] "X1"   "X1.1" "X4"   "X7"   "X8"

Notice that each name is now unique.

Example 2: Create Valid Names for Matrix

Suppose we have the following matrix in R:

#create matrix
mat 2)

#view matrix
mat

     [,1] [,2]
[1,]    1    4
[2,]    2    4
[3,]    3    6
[4,]    7    0
[5,]    2    1

#view column names of matrix
colnames(mat)

NULL

Notice that the matrix currently doesn’t have any column names.

However, we can use the make.names() function to quickly create column names:

#create column names for matrix
colnames(mat) names(1:ncol(mat))

#view updated matrix
mat

     X1 X2
[1,]  1  4
[2,]  2  4
[3,]  3  6
[4,]  7  0
[5,]  2  1

Notice that the matrix now has “X1” and “X2” as the column names.

If we’d like, we can now extract values from a specific column in the matrix using the column name:

#view values in "X1" column of matrix
mat[, 'X1']

[1] 1 2 3 7 2

Also note that you can type the following into R to read the complete documentation on how to create syntactically valid names:

?make.names

Additional Resources

The following tutorials explain how to perform other common operations in R:

How to Change Row Names in R
How to Loop Through Column Names in R
How to Use the names Function in R