Question

我试图在计算R中矩阵的逆数时使用环境缓存，如下所示（从该网址https://github.com/mehulpatel21/Data-Science-Specialization-JHU/blob/master/2)%20R%20Programming/cachematrix.R获得的代码：

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
}

为了测试代码，我定义了如下矩阵：

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

cacheSolve(d)

上面的代码给我以下错误：

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

我的测试方式不正确吗？

Answer 1

将d = as.data.frame(d)传递给函数cacheSolve(d)会产生错误然后调用m <- x$getInverse()并产生错误，因为x作为未定义getInverse（）函数的data.frame传入。

以下修复程序通过首先创建您定义的makeCacheMatrix（）并通过$set()调用设置其值，并将其传递给data.frame d

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

R中出现“尝试应用非功能”错误

1 个答案: