在 R 编程中获取或设置矩阵的维度 – dim()函数

R语言中的dim()函数用于获取或设置指定矩阵、数组或数据框的维度。

Syntax: dim(x)

Parameters:
x: array, matrix or data frame.

示例 1：

# R program to illustrate
# dim function
  
# Getting R Biochemical Oxygen Demand Dataset
BOD 
  
# Getting dimension of the above dataset
dim(BOD) 

输出：

Time demand
1    1    8.3
2    2   10.3
3    3   19.0
4    4   16.0
5    5   15.6
6    7   19.8

[1] 6 2

示例 2：

# R program to illustrate
# dim function
  
# Getting the number from 1 to 9
x <- rep(1:9)
x
  
# Calling the dim() function to
# Set dimension of 3 * 3
dim(x) <- c(3, 3)
  
# Getting the numbers
# in 3 * 3 representation
x

输出：

[1] 1 2 3 4 5 6 7 8 9

     [, 1] [, 2] [, 3]
[1, ]    1    4    7
[2, ]    2    5    8
[3, ]    3    6    9