Getting "attempt to apply non-function" error in R

Question

I am trying to use the environment caching while calculating the inverse of a matrix in R as shown below (code obtained from this url https://github.com/mehulpatel21/Data-Science-Specialization-JHU/blob/master/2)%20R%20Programming/cachematrix.R :

makeCacheMatrix <- function(x = matrix()) {
        
    ## Initialize the inverse property
    i <- NULL

    ## Method to set the matrix
    set <- function( matrix ) {
            m <<- matrix
            i <<- NULL
    }

    ## Method the get the matrix
    get <- function() {
        ## Return the matrix
        m
    }

    ## Method to set the inverse of the matrix
    setInverse <- function(inverse) {
        i <<- inverse
    }

    ## Method to get the inverse of the matrix
    getInverse <- function() {
        ## Return the inverse property
        i
    }

    ## Return a list of the methods
    list(set = set, get = get,
         setInverse = setInverse,
         getInverse = getInverse)
}


## Compute the inverse of a special matrix returned by "makeCacheMatrix"
## above. If the inverse is already calculated (and the matrix has not
## changed), then the "cachesolve" should retrieve the inverse from the cache.

cacheSolve <- function(x, ...) {
        ## Return a matrix that is the inverse of 'x'
        m <- x$getInverse()

    ## Just return the inverse if its already set
    if( !is.null(m) ) {
            message("getting cached data")
            return(m)
    }

    ## Get the matrix from our object
    data <- x$get()

    ## Calculate the inverse using matrix multiplication
    m <- solve(data) %*% data

    ## Set the inverse to the object
    x$setInverse(m)

    ## Return the matrix
    m
}

For testing the code, I have defined a matrix as follows:

d = matrix(1:1000000, 5000, 200)
d = as.data.frame(d)

cacheSolve(d)

The above code gives me the following error:

Error in x$getInverse() : attempt to apply non-function

Is my way of testing not correct?

Possible duplicate of [Caching the mean of a Vector in R](https://stackoverflow.com/questions/24904683/caching-the-mean-of-a-vector-in-r), which is the sample program for makeCacheMatrix(). — Len Greski, Mar 17 '19 at 01:11

score 1 · Accepted Answer · answered Mar 16 '19 at 12:40

The error is generated by passing d = as.data.frame(d) to your function cacheSolve(d) which then calls m <- x$getInverse() and generates the error because x is passed in as a data.frame, which does not have the getInverse() function defined.

The fix as follows enables the function to run by first creating the makeCacheMatrix() you've defined and setting its value with the $set() call, passing it the data.frame d

d = matrix(1:1000000, 5000, 200)
d = as.data.frame(d)
cm = makeCacheMatrix(d)
cm$set(d)
cacheSolve(cm)

Getting "attempt to apply non-function" error in R

1 Answers1