1- # # Put comments here that give an overall description of what your
2- # # functions do
1+ # # This solution ignores the one required by the assignment. I believe this
2+ # # solution is more flexible. That one is working with fixed function and
3+ # # arguments.
4+ # # This code presents two alternatives.
35
4- # # Write a short comment describing this function
56
6- makeCacheMatrix <- function (x = matrix ()) {
7+ # # Creates a version of a function that is able to cache the result per key.
8+ # # This allows making a cachable version of any function.
9+ # # Useful when the calling arguments are expected to change.
10+ # # Input
11+ # # - f function
12+ # # Return
13+ # # - callable function, arguments: cache key, original function arguments
14+ cachedFunctionFactory <- function (f ) {
15+ cache = list ()
16+ function (key , ... ) {
17+ if (is.null(cache [[key ]])) {
18+ cache [[key ]] <<- f(... )
19+ }
20+ cache [[key ]]
21+ }
22+ }
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24+ # # Lazy loader generator.
25+ # # Accepts any function with the called arguments.
26+ # # Useful when the arguments will not change.
27+ # # Input
28+ # # - f function
29+ # # - ... function args
30+ # # Return
31+ # # - callable lazy evaluator
32+ lazyLoadingFactory <- function (f , ... ) {
33+ cache = NULL
34+ function () {
35+ if (is.null(cache )) {
36+ cache <<- f(... )
37+ }
38+ cache
39+ }
840}
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1042
11- # # Write a short comment describing this function
43+ # # Example to matrix to invert.
44+ m <- matrix (c(2 , 5 , 1 , 2 ), 2 , 2 )
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13- cacheSolve <- function (x , ... ) {
14- # # Return a matrix that is the inverse of 'x'
15- }
46+ # # Example of using the cached function loader:
47+ cachableSolve <- cachedFunctionFactory(solve )
48+ cachedSolve(" key" m )
49+
50+ # # Example of using the lazy loader:
51+ lazySolve <- lazyLoadingFactory(solve , m )
52+ lazySolve()
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