是否有一个函数可以使用基函数证明矩阵是否为方阵？

Question

#完成模板中的代码块以编写一个接受矩阵（任意大小）M 作为参数的函数，returns 如果矩阵为正方形则为 TRUE，否则为 FALSE。它也应该适用于标量。

#我给出了第一部分代码：

```{r}

is.square <- 函数(M) {

}


#and I am required to finish the code so that it gives "TRUE" OR "FALSE" when I test the code on these examples: 

#a=2
# is.square(a)
#
# A = matrix(1:4,nrow=2,ncol=2) # is.square(A)
#
# B = matrix(1:9,nrow=3,ncol=3) # is.square(B)
#
# C = matrix(1:6,nrow=3,ncol=2) # is.square(C)


#only base functions are allowed and no matter what I try I cannot get it right. 

#I've tried 

    is.square <- function(M) {
  
  if(dim(M)[1]) != dim(M)[2]) {
    
    return(FALSE)
    
  } else {
    
    return(TRUE)
  }

}


#but get the errors 
> is.square <- function(M) {
+   
+   if(dim(M)[1]) != dim(M)[2]) {
Error: unexpected '!=' in:
"  
  if(dim(M)[1]) !="
>     
>     return(FALSE)
Error: no function to return from, jumping to top level
>     
>   } else {
Error: unexpected '}' in "  }"
>     
>     return(TRUE)
Error: no function to return from, jumping to top level
>   }
Error: unexpected '}' in "  }"
> 
> }
Error: unexpected '}' in "}"

Answer 1

我认为你在这行中有错字

(dim(M)[1]) != dim(M)[2])

应该是

(dim(M)[1] != dim(M)[2])

是否有一个函数可以使用基函数证明矩阵是否为方阵？

is there a function that can prove if a matrix is square using the base functions?

r

matrix