# Return a Matrix with Lower Triangle as TRUE values in R Programming – lower.tri() Function

• Last Updated : 16 Jun, 2020

`lower.tri()` function in R Language is used to return a matrix of logical values with lower triangle as TRUE.

Syntax: lower.tri(x, diag)

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

Example 1:

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

Output:

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

Example 2:

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

Output:

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