Lexical Scoping

Lexical Scoping...R

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+makeCacheMatrix <- function(x = matrix()) {
+  inv <- NULL
+  set <- function(y) {
+    x <<- y
+    inv <<- NULL  # Reset the cache if the matrix is changed
+  }
+  get <- function() x
+  setInverse <- function(inverse) inv <<- inverse
+  getInverse <- function() inv
+  list(set = set, get = get, setInverse = setInverse, getInverse = getInverse)
+}
+cacheSolve <- function(x, ...) {
+  # Check if the inverse is already cached
+  inv <- x$getInverse()
+
+  if(!is.null(inv)) {
+    # If cached, return the cached inverse
+    message("getting cached data")
+    return(inv)
+  }
+
+  # Otherwise, compute the inverse
+  mat <- x$get()  # Get the matrix
+  inv <- solve(mat, ...)  # Compute the inverse
+
+  # Cache the computed inverse
+  x$setInverse(inv)
+
+  # Return the computed inverse
+  inv
+}

Lexical Scoping.R

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+makeCacheMatrix <- function(x = matrix()) {
+
+  inv <- NULL  # Initialize the inverse as NULL
+
+  set <- function(y) {
+    x <<- y    # Assign new matrix value
+    inv <<- NULL  # Reset inverse cache
+  }
+
+  get <- function() x  # Retrieve the matrix
+
+  setInverse <- function(inverse) inv <<- inverse  # Store the inverse
+  getInverse <- function() inv  # Retrieve the inverse
+
+  list(set = set, get = get, setInverse = setInverse, getInverse = getInverse)
+}
+
+
+## Write a short comment describing this function
+
+cacheSolve <- function(x, ...) {
+  ## Return a matrix that is the inverse of 'x'
+  inv <- x$getInverse()
+
+  if (!is.null(inv)) {
+    message("Getting cached inverse")
+    return(inv)
+  }
+
+  data <- x$get()
+  if (nrow(data) != ncol(data)) {
+    stop("The matrix must be square to compute its inverse.")
+  }
+
+  inv <- solve(data, ...)  # Compute inverse
+  x$setInverse(inv)  # Cache inverse
+
+  inv  # Return inverse
+

Lexical_Scoping.R

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+makeCacheMatrix <- function(x = matrix()) { ## define the argument with default mode of "matrix"
+  inv <- NULL                             ## initialize inv as NULL; will hold value of matrix inverse 
+  set <- function(y) {                    ## define the set function to assign new 
+    x <<- y                             ## value of matrix in parent environment
+    inv <<- NULL                        ## if there is a new matrix, reset inv to NULL
+  }
+  get <- function() x                     ## define the get fucntion - returns value of the matrix argument
+
+  setinverse <- function(inverse) inv <<- inverse  ## assigns value of inv in parent environment
+  getinverse <- function() inv                     ## gets the value of inv where called
+  list(set = set, get = get, setinverse = setinverse, getinverse = getinverse)  ## you need this in order to refer 
+  ## to the functions with the $ operator
+}
+
+
+## Write a short comment describing this function
+## This function computes the inverse of the special "matrix" returned by makeCacheMatrix above.
+## If the inverse has already been calculated (and the matrix has not changed),
+## then cacheSolve will retrieve the inverse from the cache
+
+cacheSolve <- function(x, ...) {
+  ## Return a matrix that is the inverse of 'x'
+  inv <- x$getinverse()
+  if(!is.null(inv)) {
+    message("getting cached data")
+    return(inv)
+  }
+  data <- x$get()
+  inv <- solve(data, ...)
+  x$setinverse(inv)
+  inv
+}