wyp22215 / r-programming

The following code demonstrates how to use the makeCacheMatrixMean.R script.

Lines starting with # are simple comments, lines starting with #> are things printed in the output.

read the R script

change the directory to the directory of the file you saved

source("makeCacheMatrixMean.R")

create a square matrix (because solve only handles square matrices)

create the matrix during the call of makeCacheMatrix()

a <- makeCacheMatrix( matrix(c(1,2,12,13), nrow = 2, ncol = 2) );

summary(a); #> Length Class Mode
#> setMatrix 1 -none- function #> getMatrix 1 -none- function #> cacheInverse 1 -none- function #> getInverse 1 -none- function

a$getMatrix(); #> [,1] [,2] #> [1,] 1 12 #> [2,] 2 13

cacheSolve(a) #> [,1] [,2] #> [1,] -1.1818182 1.09090909 #> [2,] 0.1818182 -0.09090909

the 2nd time we run the function,we get the cached value

cacheSolve(a) #> getting cached data #> [,1] [,2] #> [1,] -1.1818182 1.09090909 #> [2,] 0.1818182 -0.09090909 Alternatively, the matrix can be created after calling a makeCacheMatrix without arguments.

read the R script

replace the "path/to/file" with the directory you save the file into

or you can read the file directly from the web

source("path/to/file/assessment3.R")

call makeCacheMatrix without arguments

a <- makeCacheMatrix(); summary(a); #> Length Class Mode
#> setMatrix 1 -none- function #> getMatrix 1 -none- function #> cacheInverse 1 -none- function #> getInverse 1 -none- function

create a square matrix (reason solve only handles square matrices )

#if the matrix is not square,it will prompt like this :

a<-makeCacheMatrix() summary(a) Length Class Mode
setMatrix 1 -none- function getMatrix 1 -none- function cacheInverse 1 -none- function getInverse 1 -none- function a$setMatrix(matrix(c(1,2,3,4,5,6),nrow=3,ncol=2)) a$getMatrix() [,1] [,2] [1,] 1 4 [2,] 2 5 [3,] 3 6 cacheSolve(a) #"Error in solve.default(data) : 'a' (3 x 2) must be square"

a$setMatrix( matrix(c(1,2,12,13), nrow = 2, ncol = 2) ); a$getMatrix(); #> [,1] [,2] #> [1,] 1 12 #> [2,] 2 13

cacheSolve(a) #> [,1] [,2] #> [1,] -1.1818182 1.09090909 #> [2,] 0.1818182 -0.09090909

the 2nd time we run the function, we get the cached value

cacheSolve(a) #> getting cached data #> [,1] [,2] #> [1,] -1.1818182 1.09090909 #> [2,] 0.1818182 -0.09090909