The Trycatch inside R

We know that both Java and Python have error handling mechanisms, and Java is a try ... In the form of catch, Python is try ... Except form, this kind of grasping the wrong form is very good, there are similar things in R, that is the Trycatch function, just beginning is not know, and then the R Machine learning actual combat that book code to write a time to know, specific see how to use the put:
(1) Crawl error
TryCatch (Libray (XX), Error=function (e) {print ("error occurred")})
Results:
[1] "error occurred"
The error function is executed when the XX package is wrong, and the result of the error is executed.




(2) Crawl errors and warnings
TryCatch (Libray (xx), warning = function (w) {print ("warning appears")},
Error=function (e) {print ("error occurred")})


(3) Finally will execute, similar to Python and Java
TryCatch (Libray (xx), warning = function (w) {print ("warning appears")},
Error=function (e) {print ("error occurred")},


finally={
Print ("Import Ggplot2 package")
Library (GGPLOT2)
}

)




This function is still very trial, their own code to put on the other machine to carry out, will appear in the absence of the package on the other machine, R software is not like SAS is commercial software, things are unified package, this may also be the ills of R ... In short, this function is more useful, and the rest is left to you to imagine ...