在 R 编程中生成具有指定级别的因子 - gl()函数

R 语言中的gl()函数用于通过指定因子水平的模式来生成因子。

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

示例 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)

输出：

[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

示例 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)

输出：

[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