CODEWITHSUNDEEP
rstring
James Marshall
James Marshall

Reputation: 91

Ignore a string in R

At the start of my code i assign the following values

Hierarchy_1 <- "Store_2"
Hierarchy_2 <- "Store"
Hierarchy_3 <- "SKK"

And then i assign them in the following vector, which is my stable columns of my csv. However in order to be a dynamic code there must be a case where Hierarchy_1 will not exist as a column. Is there a function to ignore Hierarchy_1 to avoid deleting it from StableCols vector and later stages of my code?

StableCols<- c(Hierarchy_1,Hierarchy_2,Hierarchy_3,DateName,DepVarName)

Upvotes: 0

Views: 744

Answers (2)

Ven Yao
Ven Yao

Reputation: 3710

You can use the get0 function.

get0 search for an object in R enviroment, return NULL if not found.

Hierarchy_1 <- "Store_2"
Hierarchy_2 <- "Store"
Hierarchy_3 <- "SKK"

StableCols<- c(get0("Hierarchy_1"), Hierarchy_2, Hierarchy_3)
StableCols
# [1] "Store_2" "Store"   "SKK" 

rm(Hierarchy_1)
StableCols<- c(get0("Hierarchy_1"), Hierarchy_2, Hierarchy_3)
StableCols
# [1] "Store" "SKK"

You can also use the dynGet function.

StableCols<- c(dynGet("Hierarchy_1", ifnotfound = NULL), Hierarchy_2, Hierarchy_3)

To David:

You are right about dynGet. I have no idea. Maybe the following info can help.

From ?get:

dynGet() is somewhat experimental and to be used inside another function. It looks for an object in the callers, i.e., the sys.frame()s of the function. Use with caution.

I tested another function mget. It also works.

StableCols<- c(unname(unlist(mget("Hierarchy_1", ifnotfound = list(NULL)))), 
               Hierarchy_2, Hierarchy_3)

Upvotes: 1

Sid
Sid

Reputation: 1

You can use rm 

c(rm(Hierarchy_1), Hierarchy_2, Hierarchy_3, DateName, DepVarName)

or you can use subset

c(subset(StableCols, StableCols!=Hierarchy_1))

Or

StableCols[-1]

will remove element at first index and print rest

Upvotes: 0

Related Questions