Generate Factors with specified Levels in R Programming – gl() Function

gl() function in R Language is used to generate factors by specifying the pattern of their levels.

Syntax:
gl(x, k, length, labels, ordered)

Parameters:
x: Number of levels
k: Number of replications
length: Length of result
labels: Labels for the vector(optional)
ordered: Boolean value to order the levels

Example 1:

# R Program to generate factors

# Creating a factor
# using gl() function
x1 <- gl(2, 5)

# gl() function with
# length specified
x2 <- gl(3, 4, 12)

# Printing the factors
print(x1)
print(x2)

Output:

 [1] 1 1 1 1 1 2 2 2 2 2
Levels: 1 2
 [1] 1 1 1 1 2 2 2 2 3 3 3 3
Levels: 1 2 3

Example 2:

# R Program to generate factors

# gl() function with
# length and labels specified
x1 <- gl(3, 4, 12, label = letters[1:12])

# gl() function with
# length, label and order specified
x2 <- gl(3, 4, 12, label = letters[1:12], ordered = T)

# Printing the factors
print(x1)
print(x2)

Output:

 [1] a a a a b b b b c c c c
Levels: a b c d e f g h i j k l
 [1] a a a a b b b b c c c c
Levels: a < b < c < d < e < f < g < h < i < j < k < l