在 R 编程中返回一个上三角为 TRUE 值的矩阵 – upper.tri()函数

R 语言中的upper.tri()函数用于返回一个逻辑值矩阵，其中上三角为 TRUE。

Syntax: upper.tri(x, diag)

Parameters:
x: Matrix object
diag: Boolean value to include diagonal

示例 1：

# R program to print the 
# upper triangle of a matrix
  
# Creating a matrix
mat <- matrix(c(1:9), 3, 3, byrow = T)
  
# Calling upper.tri() Function
# Excluding diagonal elements
upper.tri(mat, diag = F)

输出：

[, 1]  [, 2]  [, 3]
[1, ] FALSE  TRUE  TRUE
[2, ] FALSE FALSE  TRUE
[3, ] FALSE FALSE FALSE

示例 2：

# R program to print the 
# upper triangle of a matrix
  
# Creating a matrix
mat <- matrix(c(1:9), 3, 3, byrow = T)
  
# Calling upper.tri() Function
# including diagonal elements
upper.tri(mat, diag = T)

输出：

[, 1]  [, 2] [, 3]
[1, ]  TRUE  TRUE TRUE
[2, ] FALSE  TRUE TRUE
[3, ] FALSE FALSE TRUE